Lactobacillus supplementation for Helicobacter pylori eradication in children: A language-inclusive systematic review and meta-analysis of efficacy and safety

Abstract

BACKGROUND

Increasing antibiotic resistance has reduced the effectiveness of standard Helicobacter pylori (H. pylori) eradication therapies in children. Probiotics, particularly Lactobacillus species, have been proposed as adjuvants to improve treatment outcomes and reduce side effects.

AIM

To evaluate the efficacy and safety of Lactobacillus spp. alongside standard eradication therapy in pediatric populations, emphasizing globally representative evidence through inclusion of non-English studies, especially from high-prevalence regions such as China.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) from PubMed/MEDLINE, Cochrane CENTRAL, Scopus, and four Chinese databases. Primary outcome was eradication rate; secondary outcomes included overall and specific adverse events (AEs). Subgroup analyses evaluated probiotic dosage, supplementation duration, and eradication regimen.

RESULTS

Thirteen RCTs involving 1428 children were included; eight were conducted in China. Lactobacillus spp. significantly improved eradication rates [89.7% vs 72.3%; relative risk (RR) = 1.24, 95% confidence interval (CI): 1.15-1.34, I² = 45%]. The effect was most pronounced in triple therapy (RR = 1.28, 95%CI: 1.17-1.40) and with higher probiotic doses (≥ 5 × 10⁹ colony-forming units/day; RR = 1.36, 95%CI: 1.15-1.60). Lactobacillus spp. also significantly reduced overall AEs (RR = 0.50, 95%CI: 0.30-0.84), particularly diarrhea (RR = 0.49, 95%CI: 0.27-0.92), nausea/vomiting (RR = 0.66, 95%CI: 0.45-0.95), and taste disturbances (RR = 0.42, 95%CI: 0.23-0.76).

CONCLUSION

Adjunctive Lactobacillus therapy significantly enhances H. pylori eradication rates and reduces treatment-related adverse effects in children. Its benefits are dose-dependent and most evident in triple therapy regimens. Inclusion of Chinese and other non-English studies provides the most geographically comprehensive evidence to date, supporting the use of Lactobacillus probiotics as a complementary strategy to optimize H. pylori management in pediatric patients across diverse global settings.

Key Words: Probiotic; Lactobacillus; Helicobacter; Infection; Gastritis; Children

Core Tip: Adjunctive Lactobacillus supplementation significantly enhances Helicobacter pylori (H. pylori) eradication rates in children and reduces treatment-related adverse effects. Evidence from this meta-analysis, which includes a substantial number of non-English and Chinese studies, demonstrates that probiotics are particularly effective when combined with standard triple therapy and when administered at higher doses. These findings support Lactobacillus probiotics as a safe, effective, and globally relevant complementary strategy for optimizing pediatric H. pylori treatment.

INTRODUCTION

Helicobacter pylori (H. pylori), a Gram-negative, spiral-shaped, microaerophilic pathogen, colonizes the human gastric mucosa and represents one of the most widespread chronic bacterial infections globally, with an estimated prevalence affecting nearly half of the world's population[1,2]. Acquired mainly in childhood, H. pylori infection typically becomes chronic and lifelong if untreated. This persistent colonization is a well-known cause of chronic active gastritis, peptic ulcers, and duodenal ulcers, and it is a major risk factor for gastric cancer and mucosa-associated lymphoid tissue lymphoma[3-5]. The global prevalence among children remains considerable, with recent meta-analyses estimating it at approximately 30%, albeit with significant geographical disparities[6]. Current clinical guidelines, notably those from ESPGHAN/NASPGHAN, advocate for a nuanced, individualized approach to treatment in children[7]. Eradication is primarily recommended for confirmed peptic ulcer disease or other clinically significant conditions, ideally guided by antimicrobial susceptibility testing, highlighting the need for careful risk-benefit assessment, especially in incidentally detected cases[5,7]. The escalating global prevalence of H. pylori strains resistant to cornerstone antibiotics, notably clarithromycin and metronidazole, has substantially compromised treatment efficacy, leading to declining eradication success rates across numerous regions[8,9]. This mounting challenge of antimicrobial resistance has catalyzed the exploration of complementary therapeutic strategies aimed at enhancing eradication efficacy while improving treatment tolerability. Within this context, probiotics, particularly Lactobacillus supplementation[10,11], have emerged as promising adjuncts due to their ability to inhibit H. pylori adhesion, secrete antimicrobial compounds, and stabilize gut microbiota during antibiotic treatment[12-15]. While prior meta-analyses support their use[16-18], significant limitations persist, especially regarding geographic representation. A recent meta-analysis by Mishra et al[19], for instance, included only English-language studies, thereby excluding a substantial body of evidence from high-prevalence regions such as China, a critical gap given that nearly one-third of the global pediatric H. pylori burden resides in Asia[20]. To address this evidence gap and provide a more globally applicable synthesis, we conducted a systematic review and meta-analysis without language restrictions, intentionally incorporating Chinese databases to ensure representation of high-burden populations. Our aims were to evaluate the efficacy and safety of Lactobacillus spp. in children undergoing H. pylori eradication, and to examine dose- and regimen-dependent effects, thereby offering clinically actionable guidance for diverse settings, including those previously underrepresented in the literature.

MATERIALS AND METHODS

Protocol registration

This systematic review and meta-analysis was prospectively registered with the International Prospective Register of Systematic Reviews (ID: CRD420231168945). The methodology was conducted in strict accordance with the Cochrane Handbook for Systematic Reviews of Interventions and adhered to the reporting standards outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guideline[21]. The certainty of evidence for primary and secondary outcomes was systematically assessed utilizing the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework[22].

Search strategy

To minimize language bias and ensure a more representative global evidence base, our search strategy included pediatric studies published in all languages. A systematic literature search was executed across PubMed/MEDLINE, the Cochrane CENTRAL, Scopus, and four Chinese databases CNKI, database of Wanfang, VIP database, and the Chinese Biomedical Database without publication date restrictions. The search methodology employed a combination of controlled vocabulary, specifically Medical Subject Headings (MeSH) and Entree terms, alongside free-text keywords to capture all relevant evidence pertaining to the core concepts: H. pylori infections, Lactobacillus spp., and probiotic interventions. Boolean logical operators (AND, OR) were utilized to construct syntactically precise and conceptually sound search queries. To further ensure literature saturation, we manually screened the reference lists of all included studies and relevant prior reviews. The complete search strategies are provided in Supplementary Table 1.

Outcomes

Primary outcome: H. pylori eradication, defined as a negative result on a validated confirmatory test [¹³C-urea breath test (UBT), monoclonal stool antigen test (SAT), or endoscopic biopsy with histology/culture] performed ≥ 4 weeks post-treatment. Assessment followed per-protocol principles; all included studies utilized at least one validated diagnostic method.

Secondary outcomes: Treatment-related adverse events (AE), with a focus on antibiotic-associated side effects, were analyzed overall and by symptom category. Gastrointestinal events (e.g., diarrhea, nausea, vomiting, abdominal pain, bloating) were prioritized due to consistent reporting; non-gastrointestinal events (e.g., headache, allergic reactions) were also assessed. Data were extracted separately for the Lactobacillus and control groups to enable direct tolerability comparison.

Study selection

Two investigators (Ricciardi S and Dargenio VN) independently screened records at three levels: Title, abstract, and full-text, applying predefined eligibility criteria. Discrepancies were resolved through bilateral discussion, with a third senior investigator (Francavilla R) arbitrating unresolved cases.

Eligibility criteria

The eligibility criteria were defined a priori. Included studies were randomized controlled trials (RCTs) evaluating the efficacy of Lactobacillus spp. as an adjunct to first or second-line therapy for H. pylori infection exclusively in pediatric populations (0-18 years) with confirmed H. pylori infection, established through at least one validated diagnostic method (UBT, SAT, rapid urease test, histology or culture). The intervention consisted of any Lactobacillus strain or combination of strains administered concomitantly with standard eradication regimen. The comparator was an identical standard therapy regimen without probiotics. Studies employing a sequential design, wherein probiotic administration was initiated after antibiotic completion were excluded. To be included, studies were required to report at least one pre-specified primary or secondary outcome, namely H. pylori eradication rates and/or treatment-related AEs. No restrictions were applied regarding sex, ethnicity, or symptom duration. Exclusion criteria encompassed studies evaluating probiotics other than Lactobacillus spp., non-RCT designs, adult or mixed-age populations without extractable pediatric data, and non-original publications (reviews, meta-analyses, editorials, letters, conference abstracts). Studies lacking full-text availability or sufficient data for effect estimation were also excluded. For this review, “standard H. pylori eradication therapy” refers to any first- or second-line antimicrobial regimen recommended by major international pediatric guidelines, specifically including the Joint ESPGHAN/NASPGHAN Guidelines for the management of H. pylori infection in children[7].

Data extraction

Data extraction was executed using a predefined standardized form in Microsoft Excel. For every included study, the following variables were systematically extracted: First author; publication year; country of origin; study design; participant demographics (sample size, age, sex); H. pylori diagnostic methods; eradication regimen details, including proton pump inhibitor (PPI) type and dosage; specific Lactobacillus strain(s) and dosage; duration of antibiotic and probiotic therapy; follow-up method and timing; eradication outcomes in intervention and control groups; and the type and incidence of treatment-related AEs. To minimize bias, data extraction was conducted independently by two investigators (Ricciardi S and Dargenio VN), with discrepancies resolved through consultation with a third senior investigator (Francavilla R). Missing or unreported information was explicitly recorded as not available. Methodological rigor and risk of bias for all included RCTs were evaluated independently by two reviewers (Ricciardi S and Dargenio VN), utilizing the Revised Cochrane Risk-of-Bias tool (RoB 2, 2019)[23]. Bias was evaluated across five domains: (1) Randomization process; (2) Deviations from intended interventions; (3) Missing outcome data; (4) Outcome measurement; and (5) Selection of reported result. Each domain was adjudicated as conferring a “low risk”, “some concerns”, or “high risk” of bias, culminating in an overall risk-of-bias judgment for each study. Disagreements were resolved by consensus or by consultation with a third senior reviewer (Francavilla R). The certainty of evidence for each outcome was appraised using the GRADE framework, following official GRADE working group guidance and using the GRADEpro GDT software[22]. Evidence was evaluated across risk of bias, inconsistency, indirectness, imprecision, and publication bias, and graded as high, moderate, low, or very low certainty.

Statistical analysis

Analyses were performed using RevMan v7.2.0. Dichotomous outcomes (H. pylori eradication and treatment-related AEs) were assessed on a per-protocol basis and expressed as relative risks (RR) with 95% confidence intervals (CI). A DerSimonian and Laird random-effects model was used for meta-analysis to account for expected clinical and methodological heterogeneity. Between-study heterogeneity was evaluated with Cochran’s Q test and quantified with I²; I² > 50% or a Q test P value < 0.05 was considered indicative of substantial heterogeneity. To enhance precision with a limited number of studies, the Hartung-Knapp-Sidik-Jonkman adjustment was applied to 95%CI. Pre-specified subgroup analyses investigated potential effect modifiers, including: (1) Type of antibiotic regimen; (2) Duration of antibiotic therapy (7 days, 10 days or 14 days); (3) Duration of probiotic supplementation (≤ 2 weeks vs > 2 weeks); and (4) Daily probiotic dosage [< 5 × 10⁹ colony-forming units (CFU) vs ≥ 5 × 10⁹ CFU]. Subgroup estimates were derived using the Mantel-Haenszel method, with heterogeneity reported per subgroup. Sensitivity analyses evaluated the robustness of pooled estimates by iteratively excluding each study. Publication bias was assessed via funnel plot inspection and Egger’s regression test. A two-tailed P value < 0.05 defined statistical significance for all tests.

RESULTS

Study identification and selection

The study selection process is summarized in the PRISMA flow diagram (Figure 1). The database search yielded 773 records. After removal of 362 duplicates, 411 records underwent title and abstract screening, resulting in the exclusion of 292 records. The remaining 99 full-text articles were assessed for eligibility, of which 86 were excluded with reasons, leaving 13 studies meeting all inclusion criteria for qualitative and quantitative synthesis. A manual search of references yielded no additional studies. In total, 13 RCTs involving 1428 pediatric participants were included in the meta-analysis.

Figure 1  PRISMA flow chart of the search and selection process for eligible studies.

Characteristics of included studies

The final analysis included 13 RCTs published between 2005 and 2022, with geographical distribution as follows: Eight studies in China[24-31], two in Poland[32,33], and one each in the Czech Republic[34], Iran[35], and Italy[36]. The sample sizes varied considerably across studies, ranging from 40[36] participants to 211[24] participants.

All included trials evaluated adjunctive Lactobacillus spp. alongside standard H. pylori eradication therapy. While regimens primarily consisted of a PPI combined with antibiotics, substantial variation existed in the specific agents, dosages, and treatment durations employed. The study by Zhu et al[24] contained two independent intervention arms (triple therapy and sequential therapy), each with its own control group; therefore, these were treated as separate trials in the meta-analysis.

Regarding therapeutic protocols, the majority of studies (n = 11) utilized a standard triple therapy regimen based on a PPI (typically omeprazole), amoxicillin, and clarithromycin[24-26,28-35]. One study employed a triple therapy regimen incorporating furazolidone[27]. The sequential-therapy regimens consisted of omeprazole plus amoxicillin for 5 days, followed by omeprazole plus clarithromycin and tinidazole for 5 days[36], and omeprazole plus amoxicillin-clavulanate for 5 days, followed by omeprazole plus clarithromycin and metronidazole for 5 days[24]. The total duration of antibiotic treatment varied across the included studies, encompassing 7-day[29,32,34], 10-day[24-26,33,36], and 14-day[24,28,30,31,35] regimens. In one study this data was not reported[27].

Considerable diversity was observed in the probiotic interventions. The specific Lactobacillus strains investigated included Lactobacillus reuteri (L. reuteri)[35], L. reuteri ATCC 55730[36], Lactobacillus acidophilus (L. acidophilus)[25,26,28-30], L. acidophilus R0052[33], Lactobacillus Rhamnosus (L. Rhamnosus) R0011[33], Lactobacillus casei DN 114 001[34], and L. Rhamnosus GG[32]. Three studies administered a compound Lactobacillus preparation without specifying the constituent strains[24,27,31]. The daily probiotic dosage ranged from 1 × 10⁸ CFU[35,36] to 1 × 10¹⁰ CFU[34], while eight studies did not clearly report the administered dosage[24-31]. The duration of Lactobacillus spp. supplementation also varied widely, spanning from 7 days to 30 days across the trials.

A comprehensive summary of individual study characteristics, including detailed design elements and key outcomes, is presented in Table 1.

Table 1 Main characteristics of the studies included in the systematic review and meta-analysis.

Ref.	Country	No. of patients (Exp/Con)	Age, [median or mean (range)], years	Eradication regimen	Lactobacillus spp. regimen	Diagnostic methods of H. pylori
						Initial	Rechecking
Li and Zhou[31]	China	164 (82/82)	11.2 ± 2.6	Esomeprazole + amoxicillin + clarithromycin, 14 days	Compound of lactobacilli, 3 g daily, 14 days	UBT, histology	NR
Lionetti et al[36]	Italy	40 (20/20)	12.3 (3.3-18)	Omeprazole, 10 days + amoxicillin, 5 days and clarithromycin + tinidazole, 5 days	L. reuteri ATCC 55730, 108 CFU once daily, 20 days	UBT, histology, RUT	UBT
Meng[27]	China	70 (35/35)	1.7 ± 0.6 (0.6-3)	Rabeprazole + furazolidone + amoxicillin	Compound of lactobacilli, 3 times a day	UBT, histology	NR
Pan et al[28]	China	79 (38/41)	< 18	Omeprazole + amoxicillin + clarithromycin, 14 days	L. acidophilus, once daily, 28 days	UBT, histology, RUT	UBT
Plewinska et al[33]	Poland	60 (30/30)	14.1 ± 2.3 (8.8-18.3)	Omeprazole + amoxicillin + clarithromycin, 10 days	L. acidophilus R0052, L. Rhamnosus R0011, 6 × 109 CFU once daily, 30 days	Histology, RUT	Histology, RUT
Shahraki et al[35]	Iran	50 (25/25)	8.5 ± 2.5 (5-14)	Omeprazole + amoxicillin + clarithromycin, 14 days	L. reuteri, 108 CFU once daily, 28 days	Histology, SAT	UBT
Sun[26]	China	96 (48/48)	9.2 ± 0.2 (3-14)	Omeprazole + amoxicillin + clarithromycin, 10 days	L. acidophilus, 0.5 g daily, 10 days	UBT, histology	UBT, histology
Sýkora et al[34]	Czech Republic	86 (39/47)	< 18	Omeprazole + amoxicillin + clarithromycin, 7 days	L. casei DN 114 001, 1010 CFU daily, 14 days	Histology, RUT, SAT	UBT, SAT
Szajewska et al[32]	Poland	83 (44/39)	(5-17)	Omeprazole + amoxicillin + clarithromycin, 7 days	Lactobacillus GG, 109 CFU once daily, 7 days	UBT. Histology, RUT	UBT
Wang and Feng[29]	China	104 (52/52)	8.3 ± 1.2 (3-13)	Omeprazole + amoxicillin + clarithromycin, 7 days	L. acidophilus, 0.5 g daily, 7 days	UBT	UBT
Wang and Li[25]	China	96 (48/48)	< 18	Omeprazole + amoxicillin + clarithromycin, 10 days	L. acidophilus, 0.5 g daily, 28 days	UBT	UBT
Wang et al[30]	China	84 (42/42)	(3-13)	Omeprazole + amoxicillin + clarithromycin, 14 days	L. acidophilus, 0.5 g daily, 14 days	UBT, histology	UBT
Zhu et al[24]	China	211 (109/102)	< 18	Omeprazole 10 days + amoxicillin-clavulanate, 5 days, and clarithromycin + metronidazole, 5 days	Compound of lactobacilli, 10 days	UBT	UBT
Zhu et al[24]	China	205 (105/100)	< 18	Omeprazole + amoxicillin-clavulanate + clarithromycin, 14 days	Compound of lactobacilli, 14 days	UBT	UBT

CFU: Colony-forming unit; Con: Control group (standard triple therapy); Exp: Experimental group (Lactobacillus spp. + standard triple therapy); NR: Not reported; PPI: Proton pump inhibitor; RUT: Rapid urease test; SAT: Stool antigen test; UBT: Urea breath test; L. reuteri: Lactobacillus reuteri; Lactobacillus spp.: Lactobacillus species; L. acidophilus: Lactobacillus acidophilus; H. pylori: Helicobacter pylori.

Risk-of-bias assessment of included studies

Methodological quality assessment using the Cochrane Rob 2 tool revealed variable risk profiles across included studies[24-36]. Most trials showed a low risk of bias in the domains of missing outcome data and outcome measurement, indicating generally complete reporting and reliable outcome assessment. Concerns regarding the randomization process were noted in seven studies, primarily due to inadequate description of sequence generation and allocation concealment. Similarly, seven studies raised some concerns regarding deviations from intended interventions, mostly owing to insufficient details on blinding.

The domain assessing selection of reported results presented the most notable limitations: Three studies raised some concerns and two were classified as high risk of bias, suggesting potential selective outcome reporting. Despite these limitations, the overall methodological quality was deemed acceptable for quantitative synthesis, and the evidence was judged to be of moderate to high quality. Detailed risk of bias assessments are presented in Supplementary Figures 1 and 2.

Eradication rates

Thirteen RCTs, enrolling a total of 1428 pediatric patients (717 Lactobacillus spp. group, 711 control group), provided data for the meta-analysis of the primary outcome (Figure 2). Adjunctive Lactobacillus spp. significantly improved H. pylori eradication rates compared with control (89.7% vs 72.3%, respectively). The summary estimate, calculated using a random-effects model, yielded a RR of 1.24 (95%CI: 1.15-1.34), with moderate heterogeneity (I² = 45%).

Figure 2 Meta-analysis of the effect of Lactobacillus supplementation on Helicobacter pylori eradication rates. CI: Confidence interval.

In the subgroup analysis of Chinese studies (9 trials, n = 1109 participants), the pooled RR for successful eradication was 1.26 (95%CI: 1.15-1.37), indicating a statistically significant improvement in eradication rates with Lactobacillus spp. (P < 0.00001). Heterogeneity within this subgroup was moderate (I² = 59%)[24-31]. For studies conducted in other countries (5 trials, n = 319 participants), the pooled RR was 1.21 (95%CI: 1.05-1.38), also showing a significant benefit (P = 0.007) with lower heterogeneity (I² = 21%)[32-36]. The test for subgroup differences (P = 0.63) revealed no significant variation between Chinese and non-Chinese studies, indicating that the positive effect of Lactobacillus spp. on H. pylori eradication was consistent across geographic regions (Supplementary Figure 3).

Subgroup analysis by therapeutic regimen

Among trials utilizing standard triple therapy[24-26,28-35], a significant treatment effect was observed, with a pooled RR of 1.28 (95%CI: 1.17-1.40) and low heterogeneity (I² = 42%), indicating a consistent and statistically significant benefit associated with Lactobacillus spp. (Supplementary Figure 4).

Conversely, in the subgroup of studies employing sequential therapy, the pooled effect estimate failed to reach statistical significance (RR = 1.10, 95%CI: 0.96-1.25), with no observed heterogeneity (I² = 0%)[24,36]. This result indicates a non-significant trend toward benefit, the clinical relevance of which remains uncertain. The notable divergence in point estimates and confidence intervals between subgroups underscores that the choice of background antibiotic regimen substantially modifies the effect of Lactobacillus spp..

Subgroup analysis by antibiotic treatment duration

Among the five trials utilizing a 14-day regimen, a significant improvement in eradication rates was observed (RR = 1.28, 95%CI: 1.09-1.50), albeit with substantial heterogeneity (I² = 51%)[24,28,30,31,35]. Similarly, five trials employing a 10-day regimen demonstrated comparable efficacy (RR = 1.28, 95%CI: 1.06-1.55) with significant heterogeneity (I² = 69%)[24-26,33,36]. In contrast, the three trials investigating a 7-day regimen showed a non-significant positive trend (RR = 1.21, 95%CI: 0.75-1.96; I² = 46%)[29,32,34] (Supplementary Figure 5).

To address the substantial heterogeneity in the 14-day and 10-day subgroups, a sensitivity analysis was performed by sequentially excluding the study by Zhu et al[24]. This procedure substantially reduced heterogeneity in both subgroups (14-day: I² = 0%; 10-day: I² = 35%) while strengthening the effect estimates (14-day: RR = 1.36, 95%CI: 1.15-1.60; 10-day: RR = 1.34, 95%CI: 1.10-1.63), confirming the robust beneficial effect of Lactobacillus spp. in these treatment durations.

Subgroup analysis by probiotic dosage and supplementation duration

In the high-dose subgroup (≥ 5 × 10⁹ CFU/day), Lactobacillus spp. significantly improved eradication rates (2 RCTs, n = 146; 91.3% vs 64.9%; RR = 1.36, 95%CI: 1.15-1.60; I² = 0%, P = 0.0003)[33,34]. Conversely, no statistically significant benefit was observed in the low-dose subgroup (< 5 × 10⁹ CFU/day) (3 RCTs, n = 173; 69.7% vs 67.8%; RR = 1.07, 95%CI: 0.90-1.28; I² = 0%, P = 0.42)[32,35,36] (Figure 3A and B).

Figure 3 Effects of Lactobacillus supplementation on Helicobacter pylori eradication rates in subgroup analysis according to dose and duration. Forest plots illustrating the subgroup analyses based on supplementation dose and duration. A: High-dose group; B: Low-dose group; C: Long-term group; D: Short-term group. CI: Confidence interval.

Subgroup analysis by duration of Lactobacillus spp. supplementation revealed significant improvements in eradication rates for both short-term and long-term administration. The long-term subgroup (> 2 weeks) demonstrated a pooled RR of 1.33 (5 RCTs, n = 325; 95%CI: 1.14-1.57; I² = 50%, P = 0.0004)[25,28,33,35,36]. Similarly, the short-term subgroup (≤ 2 weeks) showed a significant benefit (8 RCTs, n = 1033; RR = 1.20, 95%CI: 1.12-1.29; I² = 35%, P < 0.00001)[24,26,29-32,34] (Figure 3C and D).

We performed an additional subgroup analysis focusing specifically on L. acidophilus, as it was the only probiotic strain evaluated in more than two independent studies. Five studies (228 participants in the experimental group and 231 in the control group) were included[25,26,28-30]. The pooled analysis demonstrated a statistically significant improvement in eradication rates (RR = 1.35, 95%CI: 1.19-1.52; I² = 47.6%, P < 0.05), with no significant heterogeneity observed, indicating a consistent effect across studies.

Side effects

Treatment tolerability was systematically evaluated through analysis of gastrointestinal AEs associated with eradication therapy supplemented with Lactobacillus spp.[24-36]. Twelve studies, comprising 1344 pediatric patients, provided data on the overall incidence of side effects (Figure 4)[24-29,31-36]. Meta-analysis demonstrated a statistically significant reduction in total AEs among patients receiving Lactobacillus spp. alongside eradication therapy (17.1% vs 34.5%; RR = 0.50, 95%CI: 0.30-0.84; I² = 73%; P = 0.01) (Figure 4). Sensitivity analysis confirmed the robustness of this finding, as the pooled RR remained consistent across iterations, ranging from 0.51 (95%CI: 0.29-0.90; I² = 75%; P < 0.01) to 0.45 (95%CI: 0.28-0.74; I² = 63%; P = 0.005) upon sequential exclusion of individual studies.

Figure 4 Meta-analysis of the effect of Lactobacillus supplementation on the treatment-related side effects in patients with Helicobacter pylori infection. CI: Confidence interval.

A focused analysis of specific AEs revealed significant protective effects of Lactobacillus spp. Six studies provided data on antibiotic-associated diarrhea, demonstrating a 49% RR reduction with probiotic co-administration (n = 915; 3.6% vs 9.3%; RR = 0.49, 95%CI: 0.27-0.92; I² = 0%; P = 0.03) (Figure 5A)[24-26,31-33].

Figure 5 Forest plots illustrating the effects of Lactobacillus supplementation on treatment-related side effects associated with Helicobacter pylori eradication therapy. A: Diarrhea; B: Nausea and vomiting; C: Taste disturbance.

Furthermore, Lactobacillus spp. significantly reduced the incidence of nausea and vomiting (12 RCTs, n = 1258; 4.9% vs 8.2%; RR = 0.66, 95%CI: 0.45-0.95; I² = 0%; P = 0.03) and taste disturbance (6 RCTs, n = 656; 3.6% vs 9.9%; RR = 0.42, 95%CI: 0.23-0.76; I² = 0%; P = 0.01) (Figure 5B and C).

No statistically significant differences were observed for several other AEs: Abdominal pain (5 RCTs, n = 329; RR = 0.46, 95%CI: 0.07-2.89; I² = 45%; P = 0.27), abdominal distension and flatulence (6 RCTs, n = 693; RR = 0.60, 95%CI: 0.29-1.22; I² = 0%; P = 0.12), loss of appetite (7 RCTs, n = 878; RR = 0.43, 95%CI: 0.18-1.01; I² = 0%; P = 0.05), constipation (4 RCTs, n = 362; RR = 0.45, 95%CI: 0.21-0.98; I² = 0%; P = 0.05), and halitosis (2 RCTs, n = 90; RR = 0.57, 95%CI: 0.04-7.59; I² = 76%; P = 0.74) (Supplementary Figure 6).

These findings demonstrate that adjunctive Lactobacillus spp. during antibiotic therapy confers significant protection against specific gastrointestinal symptoms, notably diarrhea, nausea, vomiting, and taste disturbances, underscoring its potential clinical utility for improving treatment tolerability.

Additional AEs reported only in single studies were documented qualitatively. These included headache, dizziness, insomnia, acid regurgitation, eructation, and heartburn, as well as dry mouth and fatigue.

Publication bias

Statistical assessment of publication bias using Egger's regression test revealed no significant asymmetry (P = 0.7497). This finding was corroborated by visual inspection of funnel plots (Supplementary Figures 7 and 8), collectively indicating minimal evidence of publication bias for the primary outcome.

The overall certainty of evidence, evaluated using the GRADE framework, was categorized as moderate for the primary outcome (eradication rate) and low for secondary outcomes (AEs), primarily due to heterogeneity. Complete GRADE assessments are detailed in Supplementary Figures 9 and 10.

DISCUSSION

This systematic review and meta-analysis provide a rigorous, contemporary synthesis of evidence from RCTs evaluating adjunctive Lactobacillus spp. for H. pylori eradication in children. A fundamental methodological advancement of our work is the implementation of a language-inclusive search strategy, which incorporated Chinese databases without linguistic restrictions. This approach stands in direct contrast to previous meta-analyses, such as that by Mishra et al[19], which were constrained by English-language restrictions, a limitation that risks language bias and systematically excludes high-quality research from regions where H. pylori burden is greatest. Our inclusive methodology therefore provides the most globally representative evidence base to date, ensuring that conclusions are not only statistically robust but also clinically relevant for populations historically underrepresented in Western-centric reviews, particularly across Asia. The pooled results demonstrate that Lactobacillus spp. significantly enhances eradication rates (RR = 1.24, 95%CI: 1.15-1.34) and substantially reduces treatment-related AEs (RR = 0.50, 95%CI: 0.30-0.84). Notably, the effect on eradication was most pronounced in patients receiving standard triple therapy, consistent with known probiotic mechanisms of action, including direct antimicrobial activity, competitive exclusion of H. pylori from gastric mucosa[37], and stabilization of the gut microbiome during antibiotic exposure[38,39]. Crucially, our subgroup analyses reveal a clear dose-response relationship: Significant benefits were observed only at probiotic doses ≥ 5 × 10⁹ CFU/day, underscoring the importance of adequate biomass to achieve meaningful colonization and physiological effect[40]. Furthermore, longer supplementation durations (≥ 14 days) were associated with superior outcomes, supporting the need for sustained probiotic presence throughout the treatment period. A distinctive feature of this meta-analysis is the substantial contribution of studies conducted in China, which constituted the majority of included trials (8 of 13). This reflects both the high endemic burden of H. pylori infection in China and the robust local research investment in adjuvant probiotic strategies. Importantly, subgroup analysis confirmed that the therapeutic benefit of Lactobacillus spp. was consistent across Chinese and non-Chinese studies (p for subgroup difference = 0.63), demonstrating a homogeneous effect that transcends geographical, genetic, and epidemiological boundaries. This finding significantly strengthens the external validity of our conclusions and suggests that the mechanism of action of Lactobacillus is broadly applicable, even in settings with high background antibiotic resistance. Probiotics, particularly lactobacilli, can attenuate this dysbiosis, produce gut-protective metabolites, and compete with opportunistic pathogens, thereby preserving gut homeostasis[41]. In particular, Lactobacillus spp. may enhance H. pylori eradication through multiple complementary mechanisms. First, several Lactobacillus strains produce bacteriocins and organic acids that directly inhibit H. pylori growth and compete for adhesion sites on the gastric mucosa, thereby reducing bacterial colonization and facilitating eradication[42]. Second, modulation of the gut microbiome appears particularly relevant in pediatric populations[43]. During antibiotic therapy, children commonly experience a decline in commensal bacteria such as Lactobacillus and Bifidobacterium species, along with overgrowth of opportunistic pathogens including Escherichia coli. Adjunctive Lactobacillus spp. helps preserve beneficial taxa and limits dysbiosis, contributing to improved gastrointestinal homeostasis and barrier integrity[43]. In addition, Lactobacillus exerts immunomodulatory effects, including enhancement of mucosal IgA secretion and upregulation of anti-inflammatory cytokines, which may support bacterial clearance and reduce mucosal inflammation[44]. Finally, by maintaining microbial balance and epithelial integrity, Lactobacillus spp. reduces antibiotic-associated gastrointestinal AEs such as diarrhea, nausea, and abdominal discomfort. This protective effect appears dose- and duration-dependent, with higher doses and longer supplementation associated with greater benefits[17,18]. Collectively, these microbiological and immunological mechanisms provide a plausible biological explanation for the improved eradication rates and enhanced tolerability observed in our meta-analysis, particularly with strains such as L. acidophilus and L. casei[17,18]. Beyond efficacy, our analysis highlights a pronounced reduction in gastrointestinal AEs, particularly diarrhea[45], nausea, and vomiting, which are primary drivers of poor treatment adherence. While the reductions in AEs were statistically significant, their clinical relevance is also noteworthy. For example, even a modest absolute reduction in diarrhea incidence can translate into meaningful improvements in patient quality of life, including decreased discomfort, fewer interruptions to daily activities or school attendance, improved sleep, and reduced need for additional medications. In pediatric populations especially, a lower frequency and severity of diarrhea and vomiting may substantially decrease distress for both patients and caregivers, enhance nutritional intake and hydration status, and reduce the likelihood of premature treatment discontinuation. By mitigating these side effects, adjunctive Lactobacillus therapy may improve protocol compliance and thus real-world eradication success. This is especially relevant in pediatric populations, where tolerability directly influences therapeutic outcomes. Furthermore, the reduction in side effects and improved eradication rates observed suggest that Lactobacillus spp. may reduce costs related to retreatment, management of complications, the need for medical consultations and loss of productivity[19,46,47]. Cost-effectiveness is further supported by the low cost of probiotic supplements relative to the potential savings from fewer AEs and higher eradication success, but optimal dosing, duration, and strain selection remain to be standardized. Our findings must be interpreted in light of certain limitations. Heterogeneity was moderate to substantial for some outcomes, reflecting clinical and methodological diversity across studies, including variations in probiotic strains, regimens, and reporting standards, as well as the reliance on partially self-reported AEs in some trials. A further limitation of the present analysis is the lack of long-term follow-up data, as most included trials assessed eradication only at short-term post-treatment intervals; therefore, the durability of eradication, recurrence rates, and any potential long-term benefits or risks associated with Lactobacillus spp. remain to be clarified in future studies with extended follow-up. Additionally, the predominance of Chinese studies, while a strength in representativeness, necessitates further validation in other geographic settings. Future research should prioritize large, multinational RCTs with standardized probiotic formulations, detailed reporting of strain-specific effects, and investigation of moderators such as timing of initiation and host microbiome characteristics.

CONCLUSION

In summary, this meta-analysis provides high-quality, globally generalizable evidence that Lactobacillus spp. is an effective and safe adjunct to standard H. pylori eradication therapy in children. By intentionally including non-English, and particularly Chinese, literature, we have bridged a critical gap in the evidence base, offering actionable insights for clinicians in high-prevalence regions worldwide. These results support the integration of specific, adequately dosed Lactobacillus probiotics into pediatric treatment protocols to enhance both efficacy and tolerability, ultimately improving patient-centered outcomes in the global fight against H. pylori.