Pharmacy & Therapeutics - May 2008 - (Page 290) Effect of Persistence with Drug Therapy on Myocardial Re-infarction one month after their initial AMI; they were folTable 1 Demographic and Clinical Characteristics lowed up for at least one month and had both Of Patients Having Acute Myocardial Infarction (AMI), pharmacy and medical claims. Figure 1 shows By Re-infarction Status how we obtained our cohort. Table 1 illustrates general demographic and No clinical characteristics and outcomes of the study Cohort Re-infarction Re-infarction sample. Patients tended to be middle-aged; apCharacteristics (n = 515) (n = 77) (n = 438) P Value proximately 60% were between 40 and 59 years of Age (years) age, and 58.1% were women. A high prevalence of 59 177 (34.4) 28 (36.4) 149 (34.0) 0.1394 (68.2%), and diabetes (54.4%) indicates deterioSex rated cardiovascular health among this group of Male 216 (41.9) 34 (44.2) 182 (41.6) patients. Female 299 (58.1) 43 (55.8) 256 (58.4) 0.6694 Most of the patients (66%) had non-transmural Race AMI during their initial diagnosis, and more than Caucasian 278 (54.0) 38 (49.5) 169 (38.6) half (54%) were Caucasian. Results from the χ2 African-American 237 (46.0) 39 (50.5) 269 (61.4) 0.0756 tests show factors associated with higher risk of and other re-infarction, including hyperlipidemia (P < 0.001), AMI type other comorbid heart disease (P < 0.01), and renal Transmural 175 (34.0) 29 (37.7) 146 (33.3) disease (P < 0.05). The impact of hypertension and Non-transmural 340 (66.0) 48 (62.3) 292 (66.7) 0.4595 diabetes was not statistically significant, but a link Comorbidities Heart disease 415 (80.6) 72 (17.4) 343 (82.6) 0.0019 was suggested. Hypertension 468 (90.9) 74 (15.8) 394 (84.2) 0.084 Most patients took beta blockers as their initial Hyperlipidemia 351 (68.2) 65 (18.5) 286 (81.5) 0.0009 drug, and the re-infarction rate appeared to be alRenal disease 96 (18.6) 22 (22.9) 74 (77.1) 0.0153 most identical for the three classes: statins Diabetes 280 (54.4) 49 (17.5) 231 (82.5) 0.0767 (14.2%), calcium-channel blockers (4.6%), and beta blockers (15.4%). Patients taking calcium-channel blockers had the highest Table 2 Re-infarction and Persistence of Drug Therapy by Index Drug discontinuation rate (64.6%), followed by patients who started with beta blockers Re-infarction Discontinued (58.2%) (Table 2). Index Drug Cohort Yes No Yes No Predicting the Likelihood Of Re-infarction or Death As summarized in Table 3, patients who discontinued PERCENT the initially prescribed drug after an AMI were more likely to have a re-infarction, when compared with the following groups: • those who were persistent with therapy (HR, 1.66, 95%; CI, 1.03–2.69; P < 0.05) • those with comorbid heart disease (HR, 2.91, 95% CI, 1.16–7.33; P < 0.05) • those with renal disease (HR, 1.80, 95% CI, 1.08–3.02; P < 0.05) • those with hyperlipidemia (HR, 2.38, 95% CI, 1.26–4.50; P < 0.05) Statin 113 (21.9) Calcium-channel blocker 110 (21.4) Beta-blocker 292 (56.7) 100.0 16 (14.2) 16 (14.6) 45 (15.4) 15.0 97 (85.8) 94 (85.4) 247 (85.6) 85.0 56 (49.6) 71 (64.6) 170 (58.2) 57.7 57 (50.4) 39 (35.5) 122 (41.8) 42.3 Table 3 Factors Associated with the Likelihood Of Acute Myocardial Re-infarction Hazard Ratio (95% Confidence Interval) Discontinuation of initial AMI-preventive drug Male sex Caucasian race vs. other Heart disease Hypertension Diabetes Renal disease Hyperlipidemia Current use of more than three antihypertensive drugs vs. fewer than two Transmural AMI vs. non-transmural AMI Age 1.66 (1.03–2.69) 1.29 (0.81–2.05) 1.45 (0.91–2.31) 2.91 (1.16–7.33) 2.24 (0.68–7.31) 1.18 (0.72–1.92) 1.80 (1.08–3.02) 2.38 (1.26–4.50) 1.01 (0.48–2.15) 1.16 (0.73–1.85) 0.99 (0.96–1.02) P Value 0.0358 0.2776 0.1139 0.0233 0.183 0.5132 0.0247 0.0074 0.9713 0.5339 0.5529 After we made adjustments for confounding clinical factors, patients’ age, race, and sex were not significant predictors of re-infarction. Although the results were not significant, they suggested that the presence of hypertension, diabetes, and the transmural type of AMI tended to increase the risk of re-infarction. continued on page 295 290 P&T® • May 2008 • Vol. 33 No. 5
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.