Background: Although patients undergoing peritoneal dialysis (PD) typically have complex treatment needs, the effect of medication regimen complexity on patient outcomes has not been thoroughly evaluated. This study aims to quantify medication regimen complexity and evaluate patient-centred outcomes including medication adherence and its determinants in patients undergoing PD. Methods: This study combined a retrospective audit of baseline data with a prospective evaluation of patient-related outcomes among patients undergoing PD at a large metropolitan dialysis centre in Australia. Medication regimen complexity was assessed using the 65-item Medication Regimen Complexity Index (MRCI), while patient outcomes were evaluated with validated self-reported questionnaires, including the 4-item Morisky–Green–Levine Scale (MGLS), EQ-5D-5L and EQ VAS. Results: A total of 131 patients participated [median age 67 (IQR 57–74) years]. Patients on PD were found to have complex medication regimens with an average MRCI score of 28.6 ± 11.4. Over half of the participants were deemed to be adherent to their prescribed medications as measured by the MGLS (n = 79; 60.3%). Male participants were more likely to be non-adherent to medications compared to female participants (OR 2.465; 95% CI 1.055–5.759). Participants with higher serum phosphate levels were 2.5 times more likely to report non-adherence to their medications (OR 2.523; 95% CI 1.247–5.104), while a higher health-related quality of life (HRQoL) was associated with medication adherence (OR 0.151, 95% CI 0.031–0.732). Conclusions: Patients on PD are prescribed complex medication regimens in addition to PD treatments that they perform at home. Patients on PD who were adherent to their medications had significantly better outcomes in terms of HRQoL and serum phosphate levels compared to non-adherent patients.
