Predicting Health Care Utilization and Charges Using a Risk Score for Poor Adherence in Pediatric Kidney Transplant Recipients

Pediatric kidney transplant recipients must follow a complicated regimen of timely adherence to immunosuppressant medication, routine blood work, and medical follow-up visits. Failure to adhere to the recommended regimen can result in medical complications and costly treatment. We developed a novel risk score to identify patients at risk for poor adherence behaviors and evaluated whether it would predict future health care utilization and charges. Our risk stratification score combined three simple pass/fail metrics of adherence derived directly from the electronic health record including standard deviation of immunosuppression drug levels, timely laboratory monitoring, and timely clinic visits as indicated by our clinical protocol. Risk for poor adherence was assessed over a three-month period. Linear regression was used to predict subsequent health care charges and utilization. Greater than 75% of patients had some degree of nonadherence risk during the study period, but there were no significant differences found on any outcomes for the overall score. However, when the individual components of the overall risk score were evaluated independently, patients with tacrolimus drug level standard deviation ≥2 (e.g., a marker of poor adherence) had greater health care utilization (e.g., hospitalizations) and increased total charges. Additionally, patients who did not follow up in clinic at least every 4 months had more ED visits and ED-related charges, but fewer hospitalizations. Regular clinic visits and minimizing drug level variation may deter future costly ED visits and hospitalizations.