A sequence symmetry analysis of the interrelationships between statins, diabetes and skin infections

Abstract

Aims: To determine statins' impact on skin infection risk in view of conflicting literature: that statins may reduce infection risk, but are also associated with diabetes mellitus, a risk factor for skin and soft tissue infections (SSTIs). Methods: Sequence symmetry analysis was performed on prescription claims (2001–2011) from the Australian Department of Veterans' Affairs to determine the interrelationships between: (i) statins and SSTIs; (ii) statins and diabetes; and (iii) diabetes and SSTIs; as well as whether statins increased the risk of SSTIs, independent of diabetes status. Chi-square tests were performed to detect differences in Index of Relative Socio-economic Advantage and Disadvantage scores of patients within each interrelationship. Prescriptions for statins, antidiabetic medication, and antistaphylococcal antibiotics were evaluated using nonidentifiable client numbers, prescription dates filled, residential electorates, and pharmaceutical codes. Adjusted sequence ratio and confidence interval were calculated at intervals of 91, 182 and 365 days for sequence symmetry analysis studies. Results: Statins were associated with: (i) significant SSTI risk (adjusted sequence ratio > 1; confidence interval >1), (ii) significant diabetes risk, and (iii) diabetic patients had increased risk of SSTIs. Diabetic and nondiabetic statin users had significantly increased risks of SSTIs, while the influence from socioeconomic status was not significant for each of the 3 relationships. Conclusions: Statins are associated with increased risk of SSTIs via direct and indirect mechanisms, probably independent of diabetes or socioeconomic statuses. We believe that clinicians should be aware of the association between statins and SSTIs, and, where appropriate, monitor blood glucose levels of statin users.