Table 4.

Results From 1:N Variable Ratio Matching in the Example of COX-2 Versus ns-NSAID Use and Gastrointestinal Bleeding, United States, 1999–2002

Caliper Width	Odds of GI Bleeding for COX-2 Inhibitor Users vs. ns-NSAID Usersa		Total No. of Patients Matched	COX-2 Inhibitor Users Matched		ns-NSAID Users Matched		GI Bleeding Events
	OR	95% CI		No.	%	No.	%	Total No. of GI Bleeding Eventsb	% of All Events Includedc	No. of Events in COX-2 Inhibitor Users	No. of Events in ns-NSAID Users
DRS
0.3 × SD logit(DRS)d	0.97	0.81, 1.16	46,888	30,073	93.85	16,815	95.48	532	96.38	354	178
0.2 × SD logit(DRS)	0.97	0.81, 1.16	46,887	30,072	93.85	16,815	95.48	532	96.38	354	178
0.1 × SD logit(DRS)	0.97	0.81, 1.16	46,882	30,069	93.84	16,813	95.47	532	96.38	354	178
0.05	1.02	0.85, 1.21	49,640	32,030	99.96	17,610	99.99	552	100.00	367	185
0.025	0.99	0.83, 1.18	49,640	32,030	99.96	17,610	99.99	552	100.00	367	185
0.01	0.96	0.80, 1.15	49,639	32,029	99.96	17,610	99.99	552	100.00	367	185
0.001	0.96	0.80, 1.15	49,599	31,996	99.86	17,603	99.95	551	99.82	366	185
0.0001	0.97	0.81, 1.17	49,344	31,848	99.39	17,496	99.35	544	98.55	363	181
PPS
0.3 × SD logit(PPS)d	0.96	0.80, 1.14	49,286	31,757	99.11	17,529	99.53	546	98.91	363	183
0.2 × SD logit(PPS)	0.96	0.80, 1.15	49,280	31,752	99.09	17,528	99.53	545	98.73	362	183
0.1 × SD logit(PPS)	0.96	0.80, 1.15	49,246	31,728	99.02	17,518	99.47	545	98.73	362	183
0.05	0.96	0.80, 1.15	49,238	31,726	99.01	17,512	99.44	546	98.91	363	183
0.025	0.95	0.80, 1.14	49,238	31,726	99.01	17,512	99.44	546	98.91	363	183
0.01	0.96	0.80, 1.15	49,237	31,725	99.01	17,512	99.44	546	98.91	363	183
0.001	0.97	0.81, 1.16	49,131	31,661	98.81	17,470	99.20	542	98.19	361	181
0.0001	1.01	0.84, 1.21	48,553	31,445	98.14	17,088	97.03	521	94.38	348	173
PS
0.3 × SD logit(PS)d	0.92	0.76, 1.10	48,143	31,700	98.93	16,443	93.37	542	98.19	363	179
0.2 × SD logit(PS)	0.91	0.76, 1.10	48,126	31,699	98.93	16,427	93.28	542	98.19	363	179
0.1 × SD logit(PS)	0.91	0.76, 1.09	48,086	31,693	98.91	16,393	93.08	540	97.83	362	178
0.05	0.93	0.77, 1.12	48,156	31,735	99.04	16,421	93.24	540	97.83	363	177
0.025	0.92	0.77, 1.11	48,111	31,733	99.04	16,378	93.00	539	97.64	363	176
0.01	0.92	0.76, 1.10	48,099	31,727	99.02	16,372	92.96	539	97.64	363	176
0.001	0.92	0.76, 1.11	47,937	31,681	98.87	16,256	92.31	537	97.28	361	176
0.0001	0.96	0.79, 1.16	45,777	30,294	94.54	15,483	87.92	502	90.94	338	164

Abbreviations: CI, confidence interval; COX-2, cyclooxygenase 2; DRS, disease risk score; GI, gastrointestinal; ns-NSAID, nonselective nonsteroidal antiinflammatory drug; OR, odds ratio; PPS, prognostic propensity score; PS, propensity score; SD, standard deviation.

^a Unadjusted OR = 1.09 (95% CI: 0.91, 1.30).

^b All events included in the matched analysis of GI bleeding. This was a subset of the total number of events in the cohort, as each matched analysis excluded persons who were unmatched, some of whom had the outcome of interest.

^c Percentage of the total number of events in the entire cohort (matched and unmatched) that were included in the matched analysis of GI bleeding.

^d SD logit(DRS) = 0.7053; SD logit(PPS) = 0.2090; SD logit(PS) = 0.5896.