Factors related to excessive polypharmacy (≥15 medications) in an outpatient population from Colombia

To determine the frequency of excessive polypharmacy (≥15 medications) in an outpatient population from Colombia and the variables associated with this condition.

A cross-sectional study using a systematised database of 6.2 million affiliates of the Colombian Health System. All patients treated uninterruptedly with 15 or more medications for 3 months (January-March 2017) were included. Sociodemographic, pharmacological, potential drug interactions, and prescribers' variables were identified.

A total of 264 patients with prescriptions of ≥15 medications were identified; with an estimated prevalence of excessive polypharmacy of 108.4 per 100 000 people. The mean age was 67.7 ± 17.8 years and 60.6% were females. The mean number of medications per patient was 20.1 ± 4.5 and 48.9% (n = 129) had 20 or more. The most used were antiulcer medications (89.0%; n = 235), antihypertensives (85.6%; n = 226), analgesic/antipyretic (80.3%; n = 212), psychiatric/neurologic medications (78.5%; n = 207), statins (67.4%; n = 178), acetylsalicylic acid (59.5%; n = 157), and vitamins (57.2%; n = 151). On average, each patient had 21.0 ± 11.4 drug-drug interactions and were attended by 6.2 ± 3.1 physicians. Being treated by seven or more physicians (OR: 5.09; 95% CI: 1.64-15.79) increased the probability of receiving more than 20 medications.

Drugs for treatment of chronic conditions prevailed, especially in elderly patients with multiple chronic conditions; however, some groups of medications without clear indications, such as antiulcer medications or vitamin supplements, also had extensive use. A main factor that increases the probability of polypharmacy greater than 20 drugs is care by seven or more physicians, which shows a fragmentation in patient care by the country's health system, without achieving co-ordination and integration between the different agents involved in medical care, also influenced by different physicians' practice patterns.