Any link of gout disease control among hypertensive patients and onset of end-stage renal disease? Results from a population-based study

Table 1 Demographic and clinical characteristics of new users of allopurinol treatment in a cohort of treated for hypertension from 1999 to 2007

All patients (n)	2752
Mean (SD) age, yr1	67 (9)
Risk factors for gout, % (n)
Advanced age (> 75 yr)1	23.0 (634)
Male1	82.8 (2278)
Obesity2	6.5 (179)
Drug use, % (n)
Thiazides3	21.1 (581)
Low dose acetylsalicylic acid3	34.3 (945)
Niacin3	0.4 (11)
Alcoholic diagnosis3	1.3 (35)
Thyroid problems3	12.9 (356)
Associated comorbidities, % (n)
Ischemic heart disease2	30.9 (849)
Heart failure2	10.5 (288)
Cardiac dysrhythmias2	12.5 (343)
Atrial fibrillation and flutter2	8.1 (224)
Peripheral vascular disease2	11.7 (321)
Cerebrovascular disease2	12.0 (330)
Dyslipidemia2	33.5 (921)
Diabetes2	20.7 (569)
Chronic kidney disease at grade 1 to 34	12.7 (350)
Acute renal failure2	4.3 (117)
Pulmonary disease (COPD/asthma)2	30.8 (847)
Dementia2	2.7 (73)
Rheumatic disease2	6.3 (174)
Gastrointestinal disease2	7.9 (218)
Drug use for gout treatment, % (n)
NSAIDs3	42.8 (1178)
Colchicine3	29.3 (806)
Intra-articular corticosteroids3	5.9 (163)
Oral corticosteroids3	2.4 (65)
Narcotics3	12.8 (353)

¹At treatment initiation;

²ICD-9 or ICD-10 identified in the 5 years preceding cohort entry;

³Pharmacologic treatment identified in the 2 years preceding cohort entry;

⁴Chronic kidney disease at grade 1 to 3 defined as having ICD-9 or ICD-10 with the absence of medication for phosphate binding or for hyperparathyroidism control. COPD: Chronic obstructive pulmonary disease; NSAIDs: Nonsteroidal anti-inflammatory drugs.

Table 2 Demographic and clinical characteristics of adherent and non-adherent patients to allopurinol treatment in a cohort of newly treated antihypertensive patients from 1999 to 2007

Variables	Adherent to allopurinol	Non-adherent to allopurinol	P-value
All patients (n)	1392	1360
Mean (SD) age (yr)1	67 (9)	67 (9)	0.4457
Risk factors for gout, % (n)
Advanced age (> 75 yr)1	22.2 (309)	23.9 (325)	0.2900
Male1	84.2 (1172)	81.3 (1106)	0.0367
Obesity2	6.4 (89)	6.6 (90)	0.8117
Drug use
Thiazides3	20.0 (278)	22.3 (303)	0.1380
Low dose acetylsalicylic acid3	35.8 (499)	32.8 (446)	0.0917
Niacin3	0.4 (5)	0.4 (6)	0.7333
Alcoholic diagnosis2	1.2 (16)	1.4 (19)	0.5622
Thyroid problems2	13.1 (182)	12.8 (174)	0.8264
Associated comorbidities, % (n)
Ischemic heart disease2	31.3 (435)	30.4 (414)	0.6460
Chronic heart failure2	10.7 (149)	10.2 (139)	0.6787
Cardiac dysrhythmias2	11.5 (160)	13.5 (183)	0.1193
Atrial fibrillation and flutter2	7.5 (104)	8.8 (120)	0.1946
Peripheral vascular disease2	12.1 (168)	11.3 (153)	0.5034
Cerebrovascular disease2	12.3 (172)	11.6 (158)	0.5509
Dyslipidemia2	35.0 (487)	31.9 (434)	0.0875
Diabetes2	21.1 (294)	20.2 (275)	0.5599
Chronic kidney disease at grade 1 to 34	12.7 (177)	12.7 (173)	0.9968
Acute renal failure2	4.3 (60)	4.2 (57)	0.8769
Pulmonary disease (COPD/asthma)2	31.4 (437)	30.1 (410)	0.4787
Dementia2	2.9 (40)	2.4 (33)	0.4656
Rheumatic disease2	5.0 (69)	7.7 (105)	0.0029
Gastrointestinal disease2	7.5 (105)	8.3 (113)	0.4571
Drug use for gout treatment3, % (n)
NSAIDs3	37.8 (526)	47.9 (652)	< 0.0001
Colchicine3	26.9 (374)	31.8 (432)	0.0048
Intra-articular corticosteroids3	6.4 (89)	5.4 (74)	0.2899
Oral corticosteroids3	1.9 (27)	2.8 (38)	0.1400
Narcotics3	12.9 (179)	12.8 (174)	0.9593

¹At treatment initiation;

²ICD-9 or ICD-10 identified in the 5 years preceding cohort entry;

³Pharmacologic treatment identified in the 2 years preceding cohort entry;

⁴Chronic kidney disease at grade 1 to 3 defined as having ICD-9 or ICD-10 with the absence of medication for phosphate binding or for hyperparathyroidism control. COPD: Chronic obstructive pulmonary disease; NSAIDs: Nonsteroidal anti-inflammatory drugs.

Table 3 Exposure to allopurinol

	Baseline	During follow-up
Patients (n)	2752	2570
Allopurinol
Mean dose used during the period (± SD)	210.9 (± 97.5)	243.3 (± 128.2)
Proportion of patients taking < 300 mg (%)	64.7 (1782)	53.5 (1374)
Proportion of patients taking 300 mg (%)	33.5 (921)	40.8 (1049)
Proportion of patients taking > 300 mg (%)	1.8 (49)	5.7 (147)
Febuxostat
Proportion of patients who received at least 1 claim of febuxostat (%)	0 (0)	0 (0)
Mean dose used during the period (± SD)	NA	NA

NA: Not applicable.

Table 4 Characteristics of patients with end-stage renal disease and their matched controls

	Cases occurring in the follow-up and their controls
	Cases (n = 22)	Controls (n = 319)
Characteristics, % (n) unless otherwise noted
Allopurinol adherence ≥ 80%	31.8 (7)	57.1 (182)
Age (mean, continuous)1	74.2 (60-78)	74.8 (60-78)
Older than 75 yr1	36.4 (8)	38.6 (123)
Ischemic heart disease2	18.2 (4)	24.8 (79)
Heart failure2	9.1 (2)	8.5 (27)
Cardiac dysrhythmias2	0 (0)	8.2 (26)
Atrial fibrillation2	0 (0)	4.7 (15)
Peripheral arterial disease2	9.1 (2)	12.5 (40)
Cerebrovascular disease2	18.2 (4)	14.7 (47)
Dyslipidemia2	13.6 (3)	29.8 (95)
Diabetes2	18.2 (4)	19.1 (258)
Chronic kidney disease with grade 1 to 33	54.6 (12)	12.9 (41)
Acute renal failure2	9.1 (2)	3.1 (10)
Pulmonary disease (COPD/asthma)2	22.7 (5)	37.6 (120)
Dementia2	4.6 (1)	1.6 (5)
Rheumatic disease2	4.6 (1)	5.6 (18)
Gastrointestinal disease2	4.6 (1)	11.3 (36)
Severity of hypertension (1-yr prior to ESRD)
No use of antihypertensive agent	4.6 (1)	8.8 (28)
Monotherapy	36.4 (8)	43.0 (137)
2 antihypertensive agents	36.4 (8)	35.1 (112)
≥ 3 antihypertensive agents	22.7 (5)	13.2 (42)

¹At treatment initiation;

²ICD-9 or ICD-10 identified in the 5 years preceding cohort entry;

³Chronic kidney disease at grade 1 to 3 defined as having ICD-9 or ICD-10 with the absence of medication for phosphate binding or for hyperparathyroidism control. COPD: Chronic obstructive pulmonary disease; ESRD: End-stage renal disease.

Table 5 Rate ratio of end-stage renal disease

	Rate ratio (95%CI)
	Cases occurring at follow-up and their controls
	Crude	Adjusted
Allopurinol adherence level
< 80%	Reference	Reference
≥ 80%	0.35 (0.14-0.89)	0.35 (0.13-0.91)
Chronic kidney disease at grade 1 to 31	8.06 (3.28-19.77)	8.00 (3.16-20.25)
Severity of hypertension (1 yr prior to ESRD)
< 3 antihypertensive agents	Reference	Reference
≥ 3 antihypertensive agents	1.94 (0.68-5.51)	1.19 (0.38-3.74)

¹Chronic kidney disease at grade 1 to 3 defined as having ICD-9 or ICD-10 with the absence of medication for phosphate binding or for hyperparathyroidism control. Chronic kidney disease and severity of hypertension were the variables used to obtain the adjusted estimators. CI: Confidence interval; ESRD: End-stage renal disease.