We report baseline socio-demographic and clinical characteristics of 8,701 patients from a Primary Health Care cohort who had a first ACS. Patients’ characteristics have been analysed overall, divided into sexes and number of study drugs prescribed. With regard to socio-demographic characteristics, the proportion of men and women in our study is not balanced (28.7% of women) and it is similar to previous studies.[13, 14, 24, 25]
We found that women were older, had greater comorbidity at baseline and received more comedications after the study event than men, probably because they were older when had the first ACS, as described in a similar cohort by Ribas et al.[25] In agreement with similar studies, we found a higher prevalence of comorbidities in women,[26–28] while men had a higher prevalence of peripheral artery disease,[29] possibly related with the higher frequency of smoking habit.
Most patients in our study (91.3%) initiated treatment for secondary prevention with antiplatelets after the first ACS, mainly with dual antiplatelet therapy, as recommended by guidelines. [8–10] Statins were the second drug more prescribed (85.7% of patients) and beta-blockers and ACEI/ARB were less prescribed. All patients with established cardiovascular disease should be treated during hospital admission and after discharge with statins, regardless of their cholesterol values.[30] ACEI/ARB might be less prescribed as they are not always recommended for all patients, they should be considered in all ST-Elevation Myocardial Infarction patients. [8–10] All study drugs were more commonly prescribed in men than women, except for ACEI/ARB, that difference between sexes was slight and not significant, probably related to higher frequency of HTA in women in our study population, because women were older than men. These results were similar to Lafeber et al [31] and Sanfélix-Gimeno et al studies.[5] Regarding comedications, anticoagulants and diuretics were the most prescribed in women, possibly related with higher frequency of heart failure and renal impairment, being loop diuretics the group most commonly prescribed.
Women initiated secondary prevention less frequently than men.[12–14, 32–34] Nevertheless, the majority of our population (79.5%) initiated treatment with three or four drugs combined, and almost half (47.7%) with four study drugs, although we found more women treated with ≤ two study drugs than with three or four. This may perhaps occur because physicians prescribed fewer drugs to older patients who were multimorbid and polymedicated.[35] Probably, the same assumption could be extended to our finding found for women and the number of drugs prescribed, because men usually suffer ACS at an earlier age.[36–38]
Zeymer et al[39] conducted an observational prospective study including 9,998 patients with ACS from June 2000 until December 2002. They reported that patients receiving four drugs were younger and patient’s characteristics according to the number of drugs prescribed were similar to our population. They found higher percentage (92.5%) with combination of four or three components and 62.6% with combination of four. The combination of beta-blockers, statins and antiplatelets was also high (39.5%). Also, they suggested that age > 75 years old is a potent predictor for not receiving therapy with four components.[34, 39, 40]
Other author already mentioned, Lafeber et al[31] conducted an observational prospective cohort study of 2,706 recently diagnosed patients clinically manifest coronary artery disease between January 1996 and February 2010. They found fewer patients (67.0%) treated with the combination of aspirin, a statin and ≥ one blood-pressure lowering agent(s).[31]
Aspirin and clopidogrel were the most frequently antiplatelets prescribed. Dual antiplatelet therapy was less frequently prescribed to women as described by previous studies,[40–42] probably because women were older.[43] Bisoprolol, enalapril, and losartan were the most prescribed beta-blockers with slight differences between sexes. The statins most commonly prescribed in both sexes were atorvastatin and simvastatin, probably because they are the statins with more experience of use
We found a strong relation in the medication prescribed between being women and older in our population, probably because women had the first ACS in older age than men. Consequently, women had lower probability to be treated with study drugs and higher probability to be treated with other comedications.
This study has some limitations inherent to electronic database studies, such as data incompleteness, loss of follow-up of patients suffering an ACS, potential confounders, non-randomised data and possible selection biases. Other limitation is that prescriptions are not linked with diagnoses in SIDIAP database. On the other hand, the strengths of our study are the large number of patients included, representativeness for the general population, complete socio-demographic and health records, long follow-up periods and real-world data. Our data is supported by previous studies and the presence of cardiovascular risk factors and outcomes has been previously validated in SIDIAP.[44–46]
This is the first work conducted with SIDIAP database which analyses the drugs prescribed for secondary prevention of cardiovascular disease. The IMPACT study is ongoing and the next step is to assess the relationship between adherence to the four pharmacological groups recommended for secondary prevention and the clinical outcomes of cardiovascular morbidity and mortality in these patients.