Association of preoperative health status with risk of complications after primary total hip arthroplasty: How useful are the measures self-rated health, ASA classification and comorbidity count?

Abstract Background Complications after surgery can be predicted using ASA classification or comorbidity count. No study has assessed the measure self-rated health (SRH) yet. Our objective was to assess the association between SRH, ASA and comorbidity count and medical complications during hospitalization, death and all-cause revision within 5years. Methods A prospective cohort study of primary elective THAs was conducted 2002-2019 including information on preoperative general health measured with SRH, comorbidity count and ASA grade. For medical complications, proportions of events per category of health measure were calculated. Risk of all-cause revision and mortality was assessed using incidence rates, reverse Kaplan-Meier and Cox regression analyses. Results Overall, 3906 patients were included (mean age 69years). The risk of a severe medicalcomplication during hospitalization was 1% and it increased with decreasing health status. Incidence rate of dying within 5years was 1.9 cases/100 P-yrs, and it increased with decreasing health status. ASA grade 3-4 was most strongly associated with death (hazard ratio (HR) 5, 95%CI 2-11) compared to ASA grade 1. Patients with poor SRH or ≥4 comorbidities had a 3 times higher risk of dying. Incidence rate of revision was 0.6 cases/100 P-yrs and increased with decreasing health status. The association was only significant in the first 3 months postoperative. For comorbidity count the adjusted HR was 4 (95%CI 2-7)), and for ASA 3-4 HR was 3 (95%CI 2-6). Conclusion SRH, ASA classification and comorbidity count showed increasing risks of complications and death with decreasing health status. ASA was most strongly associated with death. Regarding revision within 3 months both comorbidity count and ASA performed well.