Effect of hospital case mix on the hospital consumer assessment of healthcare providers and systems star scores: Are all stars the same?

Objective: We aimed to evaluate variations in patient experience measures across different surgical specialties and to assess the impact of further casemix adjustment. Background: Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) is a publicly reported survey of patients' hospital experiences that directly influence Medicare reimbursement. Methods: All adult surgical inpatients meeting criteria for HCAHPS sampling from 2013 to 2014 at a single academic center were identified. HCAHPS measures were analyzed according to published top-box and Starrating methodologies, and were dichotomized ("high" vs "low"). Multivariable logistic regression was used to identify independent associations of high patient scores on various HCAHPS measures with specialty, diagnosisrelated group complexity, cancer diagnosis, sex, and emergency admission after adjusting for HCAHPS case-mix adjusters (education, overall health status, language, and age). Results: We identified 36,551 eligible patients, of which 30.8% (n = 11,273) completed HCAHPS.Women [odds ratio (OR) 0.78, 95% confidence interval (CI) 0.72-0.85, P < 0.001], complex cases (OR 0.90, 95% CI 0.82-0.99, P = 0.02), and emergency admissions (OR 0.67, 95% CI 0.55-0.82, P < 0.001) had lesser Star scores on adjusted analysis, whereas patients with a cancer diagnosis had greater Star scores (OR 1.15, 95% CI 1.03-1.29, P = 0.01). Using general surgery as the reference, the Star scores varied significantly across 12 specialties (range OR 0.65 for plastics to 1.29 for transplant surgery). Patient responses to individual composite scores (pain, care transition, physician, and nurse) varied by specialty. Conclusions: HCAHPS case-mix adjustment does not include adjustment for specialty or diagnosis, which may result in artificially lower scores for centers that provide a high level of complex care. Further research is needed to ensure that the HCAHPS is an unbiased comparison tool.