Frailty status and outcomes of percutaneous coronary intervention in elderly patients with non-ST-elevation myocardial infarction

Table 1 Baseline characteristics of non-ST elevation myocardial infarction patients ≥ 75 years by frailty category (n = 456690), n (%)

Variable	Low frailty	Intermediate frailty	High frailty	P value
Frailty category (distribution)	173330 (37.95)	231590 (50.71)	51770 (11.34)
Female	78657 (45.38)	111047 (47.95)	26439 (51.07)	< 0.001
Male	94673 (54.62)	120543 (52.05)	25331 (48.93)	< 0.001
Race				< 0.001
White	138716 (80.03)	177282 (76.55)	37430 (72.30)
Black	12393 (7.15)	20334 (8.78)	5394 (10.42)
Hispanic	12532 (7.23)	19129 (8.26)	5042 (9.74)
Asian/Pacific islander	4998 (2.88)	8522 (3.68)	2362 (4.56)
Native American	797 (0.46)	810 (0.35)	129 (0.25)
Race: Other	3911 (2.26)	5513 (2.38)	1413 (2.74)
Income quartile				< 0.001
USD 1-USD 47999 (Q1)	46698 (26.96)	65692 (28.36)	14653 (28.30)
USD 48000-USD 60999 (Q2)	47884 (27.63)	61937 (26.74)	13093 (25.30)
USD 61000-81999 (Q3)	42807 (24.69)	55572 (24.01)	12408 (23.97)
≥ USD 82000 (Q4)	35941 (20.73)	48090 (20.89)	11616 (22.43)
Hospital region				< 0.001
Northeast	32565 (18.78)	40319 (17.42)	8196 (15.82)
Midwest	37023 (21.37)	51032 (22.03)	12217 (23.59)
South	69335 (40.03)	92377 (39.87)	20973 (40.50)
West	34399 (19.82)	47862 (20.69)	10384 (20.09)
Hospital location				< 0.001
Rural	17350 (10.01)	22559 (9.74)	4297 (8.30)
Urban non-teaching	33846 (19.54)	45161 (19.49)	9847 (19.02)
Urban teaching	122134 (70.45)	163870 (70.76)	37626 (72.69)
Hospital bed size				0.4382
Small	41278 (23.82)	54223 (23.41)	12309 (23.77)
Medium	53416 (30.82)	71741 (30.98)	16472 (31.83)
Large	78636 (45.35)	105626 (45.61)	22989 (44.40)
Charlson comorbidity index				< 0.001
Index: 1	29286 (16.90)	10362 (4.47)	1403 (2.71)
Index: 2	41525 (23.97)	29847 (12.89)	4859 (9.39)
Index: 3	102519 (59.12)	191381 (82.64)	45497 (87.90)
Comorbidity
Hypertension	154965 (89.40)	208460 (90.01)	44895 (86.72)	< 0.001
Dyslipidemia	129420 (74.70)	153680 (66.36)	29790 (57.54)	< 0.001
Diabetes	68680 (39.60)	106650 (46.05)	22445 (43.36)	< 0.001
Atrial fibrillation	54655 (31.50)	91210 (39.38)	22065 (42.62)	< 0.001
Atrial flutter	6360 (3.67)	10130 (4.37)	2210 (4.27)	< 0.001
Chronic kidney disease	45745 (26.39)	116275 (50.21)	27225 (52.59)	< 0.001
HFrEF	32635 (18.83)	59320 (25.61)	11965 (23.11)	< 0.001
HFpEF	23630 (13.63)	46060 (19.89)	9905 (19.13)	< 0.001
Obesity	22765 (13.13)	29365 (12.68)	5260 (10.16)	< 0.001
Smoking	58485 (33.74)	80570 (34.79)	13520 (26.12)	< 0.001
Cannabis use	350 (0.20)	480 (0.21)	70 (0.14)	< 0.001
Peripheral vascular disease	16150 (9.32)	25230 (10.89)	4675 (9.03)	< 0.001
Obstructive sleep apnea	15325 (8.84)	20245 (8.74)	3115 (6.02)	< 0.001
Cerebral infarct	980 (0.57)	8325 (3.59)	6735 (13.01)	< 0.001
Hemorrhagic stroke	370 (0.21)	1770 (0.76)	1235 (2.39)	< 0.001
COPD	29870 (17.23)	57500 (24.83)	11700 (22.60)	< 0.001
Depression	11630 (6.71)	24685 (10.66)	6150 (11.88)	< 0.001
Outcomes
PCI	60682 (35.03)	38926 (16.79)	3894 (7.51)	< 0.001
AKI	22178 (12.81)	116223 (50.17)	37091 (71.66)	< 0.001
AKI requiring dialysis	173 (0.10)	5740 (2.44)	2855 (5.40)	< 0.001
ARF	19737 (11.37)	100938 (43.54)	29270 (56.54)	< 0.001
ARF requiring mechanical ventilation	1851 (1.03)	22222 (9.59)	8107 (19.49)	< 0.001
Pulmonary edema	1858 (1.02)	4913 (2.12)	1219 (2.26)	< 0.001
Transient ischemic attack	584 (0.34)	1542 (0.66)	420 (0.79)	< 0.001
Stroke	983 (0.57)	8521 (3.59)	6774 (13.01)	< 0.001
Cardiogenic shock	4492 (2.58)	22898 (9.88)	6578 (12.79)	< 0.001
Cardiogenic shock requiring MCS	1085 (0.63)	3995 (1.73)	675 (1.3)	< 0.001
Cardiac arrest	2729 (1.57)	13061 (5.73)	4083 (7.86)	< 0.001
Hypotension	6852 (3.91)	27516 (11.95)	8725 (16.81)	< 0.001
Pulmonary embolism	2064 (1.19)	5402 (2.31)	1434 (2.73)	< 0.001
Delirium	293 (0.17)	6670 (2.93)	4799 (9.24)	< 0.001
Bleed complication	11992 (6.90)	32802 (14.17)	10421 (20.13)	< 0.001
Major bleeding	2826 (1.65)	9548 (4.09)	3259 (6.26)	< 0.001

P < 0.05 is considered to be statistically significant.

HFrEF: Heart failure with reduced ejection fraction; HFpEF: Heart failure with preserved ejection fraction; COPD: Chronic obstructive pulmonary disease; PCI: Percutaneous coronary intervention; AKI: Acute kidney injury; ARF: Acute respiratory failure; MCS: Mechanical circulatory support.

Table 2 Adjusted odds ratios for in-hospital outcomes (percutaneous coronary intervention vs no percutaneous coronary intervention) among non-ST-elevation myocardial infarction patients ≥ 75 years by frailty category

Outcome	Low frailty (OR, 95%CI, P value)	Intermediate frailty (OR, 95%CI, P value)	High frailty (OR, 95%CI, P value)	Interaction
				Intermediate vs low frailty (OR, 95%CI, P value)	High vs low frailty (OR, 95%CI, P value)
Mortality	0.27 (0.22-0.32), < 0.001	0.37 (0.33-0.40), < 0.001	0.43 (0.34-0.54), < 0.001	1.56 (1.27-1.93), < 0.001	1.83 (1.37-2.44), < 0.001
Acute kidney injury	0.79 (0.75-0.82), < 0.001	0.83 (0.78-0.87), < 0.001	1.09 (0.91-1.30), 0.35	1.06 (0.97-1.15), 0.21	1.36 (1.12-1.64), 0.001
Acute kidney injury requiring dialysis	0.92 (0.78-1.09), 0.35	0.84 (0.38-1.88), 0.67	1.83 (1.42-2.36), < 0.001	0.91 (0.40-2.08), 0.82	1.99 (1.46-2.72), < 0.001
Acute respiratory failure	0.45 (0.42-0.49), < 0.001	0.69 (0.66-0.73), < 0.001	0.89 (0.76-1.03), 0.12	1.65 (1.50-1.82), < 0.001	2.13 (1.79-2.52), < 0.001
Acute respiratory failure with mechanical ventilation	0.35 (0.27-0.47), < 0.001	0.63 (0.57-0.69), < 0.001	1.00 (0.83-1.22), 0.99	1.78 (1.33-2.39), < 0.001	2.79 (1.98-3.93), < 0.001
Pulmonary edema	0.64 (0.50-0.82), < 0.001	1.13 (0.96-1.33), 0.13	1.73 (1.16-2.56), 0.007	1.98 (1.48-2.65), < 0.001	3.00 (1.89-4.76), < 0.001
Transient ischemic attack	0.70 (0.45-1.08), 0.11	1.04 (0.76-1.43), 0.79	2.45 (1.29-4.69), 0.006	1.55 (0.90-2.66), 0.11	3.04 (1.42-6.51), 0.004
Stroke	0.38 (0.26-0.57), < 0.001	0.57 (0.48-0.67), < 0.001	0.86 (0.68-1.08), 0.20	1.60 (1.04-2.44), 0.03	2.48 (1.57-3.92), < 0.001
Cardiogenic shock	0.53 (0.45-0.62), < 0.001	1.06 (0.98-1.16), 0.15	1.79 (1.48-2.17), < 0.001	2.03 (1.70-2.43), < 0.001	3.35 (2.61-4.30), < 0.001
Shock with mechanical circulatory support	1.06 (0.79-1.44), 0.66	4.52 (3.86-5.29), < 0.001	12.09 (8.23-17.76), < 0.001	4.37 (3.17-6.03), < 0.001	11.99 (7.50-19.16), < 0.001
Cardiac arrest	0.54 (0.44-0.67), < 0.001	0.78 (0.69-0.87), < 0.001	1.24 (0.96-1.61), 0.09	1.46 (1.15-1.85), 0.002	2.28 (1.64-3.18), < 0.001
Hypotension	0.83 (0.73-0.95), 0.006	1.18 (1.09-1.27), < 0.001	1.31 (1.09-1.58), 0.005	1.41 (1.22-1.62), < 0.001	1.54 (1.24-1.92), < 0.001
Pulmonary embolism	0.29 (0.22-0.39), < 0.001	0.29 (0.22-0.37), < 0.001	0.45 (0.24-0.85), 0.01	0.99 (0.66-1.46), 0.96	1.55 (0.77-3.12), 0.22
Delirium	0.70 (0.38-1.29), 0.25	0.96 (0.83-1.11), 0.57	1.60 (1.28-2.00), < 0.001	1.28 (0.71-2.32), 0.41	2.20 (1.18-4.09), 0.01
Bleeding	0.43 (0.39-0.48), < 0.001	0.80 (0.74-0.86), < 0.001	1.27 (0.98-1.67), 0.07	1.86 (1.64-2.11), < 0.001	2.82 (2.30-3.46), < 0.001
Bleeding with transfusion	0.27 (0.20-0.35), < 0.001	0.69 (0.60-0.79), < 0.001	1.28 (0.98-1.67), 0.07	2.63 (1.97-3.51), < 0.001	4.62 (3.18-6.74), < 0.001
Length of stay (days)	−0.90 (−0.98 to −0.82), < 0.001	−0.16 (−0.34 to 0.01), 0.07	+2.47 (+1.68 to +3.26), < 0.001	+0.82 (+0.64 to +0.99), < 0.001	+3.63 (+2.83 to +4.43), < 0.001
Total charges (in USD)	+$46247 (43651 to 48844), < 0.001	+$69008 (64291 to 73724), < 0.001	+$111550 (96015 to 127084), < 0.001	+$27665 (22945 to 32386), < 0.001	+$72538 (57002 to 88074), < 0.001

P < 0.05 is considered statistically significant.

Multivariable regression models were adjusted for age, sex, race/ethnicity, hospital region, hospital bed size, hospital location/teaching status, Charlson Comorbidity Index, frailty category, PCI status, and interaction terms between PCI and frailty categories (frailty 2 and frailty 3). Models accounted for the complex survey design of the NIS using discharge weights (DISCWT), strata (NIS_STRATUM), and primary sampling units (HOSP_NIS).

Table 3 Independent predictors of in-hospital mortality by frailty category and percutaneous coronary intervention status

Variable	Low frailty	Intermediate frailty	High frailty	Interaction
	OR (95%CI, P value)	OR (95%CI, P value)	OR (95%CI, P value)	OR (95%CI, P value)
Intermediate vs low frailty without PCI	-	-	-	4.72 (4.39-5.08), 0.001
High vs low frailty without PCI	-	-	-	7.71 (7.09-8.39), 0.001
PCI effect in intermediate vs low frailty	-	-	-	1.56 (1.27-1.93), 0.001
PCI effect in high vs low frailty	-	-	-	1.83 (1.37-2.44), 0.001
Age	1.07 (1.06-1.08), < 0.001	1.01 (1.01-1.02), 0.001	1.00 (0.99-1.01), 0.918	1.02 (1.01-1.02), 0.001
Female (vs male)	0.93 (0.82-1.07), 0.310	0.78 (0.74-0.83), 0.001	0.82 (0.74-0.90), 0.001	0.81 (0.77-0.84), 0.001
Race ref: White
Black	0.93 (0.72-1.19), 0.556	0.94 (0.84-1.04), 0.201	1.18 (1.01-1.38), 0.032	0.99 (0.91-1.07), 0.804
Hispanic	0.85 (0.66-1.09), 0.202	0.91 (0.82-1.01), 0.066	0.93 (0.79-1.10), 0.389	0.90 (0.83-0.98), 0.017
Asian/Pacific Islander	1.05 (0.71-1.55), 0.801	1.14 (1.00-1.30), 0.052	1.21 (0.97-1.51), 0.085	1.15 (1.03-1.29), 0.013
Native American	0.49 (0.12-2.03), 0.327	1.09 (0.71-1.68), 0.691	1.29 (0.54-3.09), 0.572	1.05 (0.72-1.52), 0.799
Race: Other	0.91 (0.59-1.39), 0.652	1.09 (0.92-1.29), 0.333	1.35 (1.03-1.75), 0.028	1.13 (0.98-1.29), 0.084
Income quartile ref: USD 47999 (Q1)
USD 48000-USD 60999 (Q2)	0.91 (0.77-1.08), 0.286	0.86 (0.80-0.92), 0.001	1.00 (0.88-1.14), 0.974	0.89 (0.84-0.94), 0.001
USD 61000-81999 (Q3)	0.83 (0.69-1.00), 0.055	0.84 (0.78-0.91), 0.001	0.94 (0.82-1.08), 0.365	0.86 (0.81-0.91), 0.001
≥ USD 82000 (Q4)	0.75 (0.61-0.92), 0.007	0.83 (0.76-0.91), 0.001	0.90 (0.78-1.04), 0.161	0.84 (0.78-0.90), 0.001
Hospital region ref: Northeast
Midwest	1.03 (0.83-1.26), 0.809	0.85 (0.78-0.93), 0.001	0.74 (0.63-0.87), 0.001	0.85 (0.79-0.91), 0.001
South	1.12 (0.93-1.34), 0.242	0.89 (0.82-0.97), 0.005	0.69 (0.60-0.80), 0.001	0.87 (0.81-0.93), 0.001
West	1.15 (0.93-1.43), 0.190	1.00 (0.91-1.09), 0.973	0.90 (0.76-1.05), 0.183	0.99 (0.92-1.07), 0.841
Hospital location Ref: Non-teaching
Teaching	0.97 (0.88-1.07), 0.531	1.04 (0.99-1.08), 0.107	1.04 (0.96-1.12), 0.384	1.03 (0.99-1.06), 0.153
Hospital bed size ref: Small
Medium	1.07 (0.90-1.26), 0.443	1.15 (1.06-1.24), 0.001	1.05 (0.93-1.19), 0.449	1.12 (1.05-1.19), 0.001
Large	0.90 (0.77-1.06), 0.215	1.18 (1.10-1.27), 0.001	1.13 (1.00-1.28), 0.049	1.13 (1.07-1.20), 0.001
Charlson comorbidity index Ref: 1
2	1.25 (1.00-1.56), 0.046	1.12 (0.97-1.29), 0.123	0.97 (0.72-1.31), 0.856	1.15 (1.03-1.28), 0.011
3	1.28 (1.05-1.55), 0.013	0.97 (0.85-1.10), 0.621	0.84 (0.65-1.10), 0.209	1.02 (0.93-1.13), 0.679

P < 0.05 is considered statistically significant.

PCI: Percutaneous coronary intervention.