Table 4.

Effect of the number of medication classes on outcomes among nursing home residents after myocardial infarction stratified by functional impairment

Outcome	Functional Impairment Categories	No. of Medications	Events / n	Risk (%)	Crude OR (95% CI)	IPTW OR (95% CI)	P for Effect Modification*
Mortality	No to Mild Impairment	1	67 / 600	11.2	Reference	Reference	0.79
		2	51 / 569	9.0	0.78 (0.53–1.15)	0.92 (0.62–1.37)
		3 or 4	32 / 522	6.1	0.52 (0.34–0.81)	0.80 (0.49–1.29)
	Moderate to Severe Impairment	1	161 / 1,225	13.1	Reference	Reference
		2	127 / 1,003	12.7	0.96 (0.75–1.23)	1.02 (0.78–1.33)
		3 or 4	71 / 868	8.2	0.59 (0.44–0.79)	0.72 (0.52–0.99)
Rehospitalization	No to Mild Impairment	1	134 / 600	22.3	Reference	Reference	0.65
		2	140 / 569	24.6	1.11 (0.84–1.46)	1.11 (0.83–1.49)
		3 or 4	128 / 522	24.5	1.07 (0.81–1.41)	1.13 (0.83–1.55)
	Moderate to Severe Impairment	1	315 / 1,225	25.7	Reference	Reference
		2	273 / 1,003	27.2	1.05 (0.87–1.27)	0.95 (0.78–1.17)
		3 or 4	233 / 868	26.8	0.98 (0.80–1.20)	0.89 (0.70–1.14)
Functional Decline	No to Mild Impairment	1	46 / 600	7.7	Reference	Reference	0.44
		2	71 / 569	12.5	1.67 (1.13–2.48)	1.47 (0.96–2.28)
		3 or 4	68 / 522	13.0	1.70 (1.14–2.53)	1.45 (0.92–2.29)
	Moderate to Severe Impairment	1	213 / 1,225	17.4	Reference	Reference
		2	203 / 1,003	20.2	1.20 (0.97–1.50)	0.95 (0.74–1.20)
		3 or 4	219 / 868	25.2	1.52 (1.22–1.88)	1.02 (0.79–1.32)

Abbreviations: OR, odds ratio; CI, confidence interval; IPTW, inverse probability of treatment-weighted.

^*Presented for the IPTW estimates only.