Association between Charlson Comorbidity Index and polypharmacy: a retrospective database study from Jordan

Objectives Polypharmacy is usually associated with duplication of therapy, unnecessary medications and adverse drug reactions. Therefore, it is crucial to study the factors that increase the risk of polypharmacy. The objective of this study was to assess the risk factors for polypharmacy (i.e. the concomitant use of at least five medications) with a special focus on comorbidity in Jordan. Methods Using a retrospective cross-sectional study design, medical records of patients (age >= 55 years), which covered slightly over one-fourth of the population, found in a national electronic healthcare database from 2018 to 2019 were retrieved. Polypharmacy, the main outcome, was defined as the current use of at least five medications (the patient should have at least one chronic condition, one medication refill and continuous use of the medication for at least 30 days). Comorbidity, the main exposure, was summarized using the Charlson Comorbidity Index (CCI). Potential predictors of polypharmacy were examined using a multivariable logistic regression analysis. Key findings An eligible sample of 113 834 individuals (mean age 68 years, 51.5% female) were included in the analysis, of whom 38% met the polypharmacy definition (28% were categorized as having major [5-9 medications] and 10.2% exhibited excessive polypharmacy [>= 10 medications]). Approximately, 20% of the patients had a CCI of >= 1. The most significant predictors of polypharmacy were a CCI score between 3 and 4 (adjusted odds ratio [AOR] = 5.89; 95% CI, 5.10 to 6.80; P< 0.001), gender (AOR = 0.86; 95% CI, 0.82 to 0.86; P< 0.001), and age >= 75 years (AOR = 1.62; 95% CI, 1.57 to 1.67; P < 0.001). Conclusions Polypharmacy is common among patients in Jordan. Comorbidity is positively, independently and strongly related to polypharmacy. Identifying groups who are at the greatest risk for polypharmacy can help optimize patients' treatment, which can lead to better outcomes and improved quality of life.