Use of Statins in Kidney Transplant Recipients in Norway

Abstract

Kidney transplant recipients (KTRs) experience increased risk of cardiovascular disease. Guidelines recommend HMG-CoA reductase inhibitor (statin) therapy when tolerated. We aimed to study changes in the prescription of statins and patients' adherence to treatment over time. A population-based observational study utilizing linked data from the Norwegian Renal Registry (national coverage of 99.9%) and the Norwegian Prescription Database was performed. Data from a total of 2250 first KTRs were included (mean age-54 years, 69% men). Dispensed prescriptions of statins and immunosuppressants for the period 2004-2016 for all first KTRs engrafted in the period 2005-2015 were analyzed. Seventy-two percent received statins the first year after kidney transplantation and the proportion increased with age. The proportion receiving a statin varied according to the time frame of transplantation (77% in 2005-2010 vs. 66% in 2012-2015). Among new users of statins, 82% of the patients were adherent both the second and third year after kidney transplantation, while the corresponding figure for those already receiving statins before transplantation was 97%. Statin continuation rates in KTRs were high. In conclusion, our findings show a slightly lower overall proportion of patients receiving statins after kidney transplants than the national target level of 80%. The proportion of statin users increased with the age of the KTRs but showed a decreasing trend as time progressed.

Keywords: cardiovascular disease; kidney transplant recipients; medication adherence; medication appropriateness; pharmacoepidemiology; prescriptions; statins.

Figure 1

Proportion (%) of patients with statins dispensed one year (1–365 days) after and/or one year (364–0 days) before the first kidney transplant (Tx) in total and according to sex and age group. The number of KTRs is given in the right margin. ¹ Use before but no use after Tx; ² Use both before and after Tx; ³ No use before but use after Tx; ⁴ No use before or after Tx.

Figure 2

Proportion (%) of kidney transplant recipients according to year of transplantation (2005–2015) with statins dispensed in the first year after transplantation in total, and according to sex (with 95% confidence intervals). Tx—transplantation.

Figure 3

Adherence to statin treatment measured as the proportion (%) of new and recurrent users who had at least one statin dispensed the first year (year 1) after transplantation, according to sex. Year 2 includes those using statins both the first and second year, and year 3 includes patients using statins all three years after transplantation. The denominator is those still alive 2 and 3 years after transplantation, respectively. Tx–transplantation.

Figure 4

Proportion (%) of patients with no statin dispensed the first year after transplantation who initiated with statins within 2-, 3- and 4 years after Tx in the age groups <40 and ≥40 years. The denominator is those still alive 2, 3 and 4 years after transplantation, respectively. Tx–transplantation.