IJCS | Volume 31, Nº4, July / August 2018

386 Borges et al. Adherence score Int J Cardiovasc Sci. 2018;31(4)383-392 Original Article Table 2 - Predictive variables by International Normalized Ratio (INR) values (normal/altered) Variables Categories Normal INR Altered INR p-value % Nº % Educational attainment Elementary 160 64.8 217 60.3 0.03 High-school 59 23.9 94 26.1 College 28 11.3 49 13.6 Family income < MWs 128 51.8 217 60.3 0.08 3 - 7 MWs 87 35.2 110 30.6 > 7 MWs 32 13 33 9.2 Use of medication Correct use 237 96 188 52.2 < 0.001 Higher dose 2 0.8 43 11.9 Lower dose 8 3.2 129 35.8 Drug-drug interaction Yes 5 2.0 132 36.7 < 0.001 No 242 98.0 228 63.3 Invasive procedures Minimum risk 1 0.4 32 8.9 < 0.001 Maximum risk 1 0.4 33 9.2 No change 245 99.2 295 81.9 Drug-food interaction Increased the intake 2 0.8 44 12.2 < 0.001 Decreased the intake 3 1.2 40 11.1 No change 242 98 276 76.7 Physical activity Active 3 1.2 17 4.7 0.02 Non-active 2 0.8 14 3.9 Not reported 242 98 329 91.4 Clinical conditions Influenza and similar conditions 5 2 29 8.1 < 0.001 Diarrhea, vomiting 4 1.6 17 4.7 Clinical and invasive infections 4 1.6 34 9.4 Not reported 234 94.7 280 77.8 Other factors Yes 15 6.1 132 36.7 < 0.001 No 232 93.9 228 63.3 Drug-related complications Yes 2 0.8 24 6.7 < 0.001 No 245 99.2 336 93.3 griseofulvin, nafcillin, rifampicin, sucralfate and trazodone. These drugs may decrease INR results, and hence, increase the risk for thromboembolic events. 7 Drug interactions related to OAC-T are of more or less importance, and are associated with processes that involve many pharmacodynamic and pharmacokinetic mechanisms – altered platelet function (clopidogrel, salicylic acid), gastrointestinal lesion (nonsteroidal anti- inflammatory drugs), impaired vitamin K synthesis in the gastrointestinal tract (antibiotics - amoxicillin, ampicillin, cephalosporin, metronidazole, clarithromycin, norfloxacin and trimethoprim/sulfamethoxazole),