AimsWe estimated overall refill adherence to all antihypertensive [AHT] and/or lipid-lowering drugs in the treatment regimen and its association with cardiovascular disease (CVD) in adults with type 1 diabetes, taking kidney disease into account. MethodsThis Finnish Diabetic Nephropathy Study involved 1,558 adults with type 1 diabetes who had purchased AHT and/or lipid-lowering drugs within ± 0.5 year from baseline and were followed until their first CVD event, death, or end of 2015. Proportion of days covered (PDC) method was used to calculate adherence. The adherence was classified as good (≥80 %), intermediate (≥50 and < 80 %) or poor (<50 %). ResultsMedian adherence rate was 74 % (IQR 63–84 %). Both good (OR 0.55 [95 % CI 0.33, 0.92], P=0.02) and intermediate (0.47 [0.29, 0.77], P=0.003) adherence were associated with lower odds of CVD, compared to poor adherence. Moreover, the higher the adherence percentage point in those with moderate albuminuria, the lower was the odds for CVD (0.81 [0.67, 0.98], P=0.03, per 10 unit increase in adherence). ConclusionsIn adults with type 1 diabetes, refill adherence of 50% or more to cardio-protective medications is associated with lower odds of incident CVD. Our findings highlight the relevance of going beyond prescribing protective CVD drugs, ensuring, and improving medication adherence matters.