Cardiovascular related polypharmacy and its association with liver and kidney impairment amongst individuals on lipid-lowering therapy: a cross-sectional study using primary care data

Abstract Background Individuals with risk factors for cardiovascular disease (CVD) frequently require concurrent treatment with various medications, a phenomenon known as polypharmacy. This study aimed to investigate the association between CVD-related polypharmacy and the presence of liver and kidney impairment amongst patients receiving lipid-lowering therapy within the Australian primary care setting. Methods This study utilised electronic medical records from general practices retrieved between January 2013 and December 2023. Multivariate logistic regression identified independent risk factors associated with CVD-related polypharmacy, defined as the concurrent use of five or more CVD protective medications. The analysis included individuals on lipid lowering therapy who are at risk for CVD. The relationship between CVD-related polypharmacy and the presence of liver and kidney dysfunction was further assessed, defined by exceeding established reference ranges for relevant biomarkers (alanine aminotransferase [ALT], aspartate aminotransferase [AST], bilirubin, creatinine, and estimated glomerular filtration rate [eGFR]) as per Australian guidelines. Results A total of 13,568 participants (median age: 63 years [IQR 54-72], 54% males) were included. Independent factors associated with CVD-related polypharmacy included diabetes (OR=5.40, 95% CI: 4.96-5.93), chronic kidney disease (CKD) (OR=2.39, 95% CI: 2.00-2.86), hypertension (OR=1.91, 95% CI: 1.75-2.07), and smoking (OR=1.05, 95% CI: 0.97-1.14). Compared to the 18-35 age group, individuals aged ≥80 years displayed a significantly higher likelihood of CVD-related polypharmacy (OR=8.17, 95% CI: 5.47-12.21). While no significant association was observed between CVD-related polypharmacy and liver impairment (OR=1.19, 95% CI: 0.59-2.37), an independent positive association was identified with kidney impairment (OR=1.38, 95% CI: 1.24-1.54), adjusted for established CVD risk factors including age, sex, smoking, diabetes, hyperlipidaemia, hypertension, and CKD. Conclusion This study suggests a positive association between CVD-related polypharmacy and increased risk of kidney impairment in Australian primary care. Further research is warranted to explore potential causal mechanisms and evaluate the efficacy of medication review strategies, enhanced kidney function monitoring, and potential medication deprescribing in managing patients at risk of CVD who are on multiple medications.