OBJECTIVES: To explore refill adherence to prescribed treatment for chronic heart failure (CHF) and/or chronic obstructive pulmonary disease (COPD), during and after a remote person-centred care (PCC) intervention. DESIGN: Post hoc analysis of a randomised controlled trial cohort. SETTING: We used data from the PROTECT (Person-Centred Care at Distance) randomised controlled trial in Swedish primary care, which were linked to data from the Swedish Prescribed Drug Register. PARTICIPANTS: A total of 222 participants from nine primary care centres were enrolled in PROTECT. This study included participants with dispensed medications for CHF and/or COPD, excluding those with multidose dispensing (intervention n=50; control n=49, 42% women, mean age 69 years). INTERVENTIONS: PROTECT evaluated a PCC intervention using a digital platform and structured telephone support in addition to usual care versus usual care alone. OUTCOME MEASURES: Refill adherence was compared between groups, defining appropriate medication supply as ≥80% of days covered over 2 years. We also examined associations between refill adherence and number of long-term conditions and medications. RESULTS: Refill adherence did not differ significantly between groups. A higher number of long-term conditions was associated with lower odds of refill adherence (adjusted OR (aOR) per additional condition: 0.71; 95% CI 0.50 to 0.97; p=0.041), as were more long-term medications (aOR per additional medication class: 0.84; 95% CI 0.71 to 0.98; p=0.029). CONCLUSIONS: The PROTECT intervention did not improve refill adherence, suggesting that future person-centred interventions may require more structured medication-management focus. Increasing numbers of long-term conditions and medications were both associated with lower refill adherence. TRIAL REGISTRATION NUMBER: NCT03183817.