A Retrospective Cohort Study on the Influence of Comorbidity on Soft Tissue Reactions, Revision Surgery, and Implant Loss in Bone-anchored Hearing Implants.

Abstract

To identify risk factors for complications after bone-anchored hearing implant (BAHI) surgery. Retrospective cohort study. Tertiary referral center. All adult patients who received titanium bone-anchored hearing implants at our clinic between September 1, 1988 and December 31, 2007 were approached to fill out a questionnaire on comorbidity factors. A total of 581 patients with 669 implants were included in the analysis. Implant loss, soft tissue reactions, and revision surgery after BAHI implantation. Skin disease and profound learning difficulties were risk factors for time to first soft tissue reaction, hazard rate ratio of 3.41 (95% CI 1.45-8.01) and 3.42 (1.03-11.39), respectively. Female gender showed a trend toward a negative risk for time to first soft tissue reaction, hazard rate ratio 0.60 (0.35-1.03). In multivariable analysis, skin disease and female gender were observed as independent associative factors, adjusted hazard ratio 3.08 (1.32-7.16) and 0.56 (0.33-0.94). For revision surgery, female gender and cardiovascular disease were identified as negative risk factors in univariable analysis, and smoking showed a trend toward a negative risk, with hazard ratios of 0.15 (0.07-0.32), 0.07 (0.03-0.20), and 0.51 (0.24-1.07), respectively. In multivariable analysis, smoking and female gender were observed as independent associative factors, adjusted hazard ratio 0.45 (0.22-0.95) and 0.14 (0.06-0.30). Smoking could be identified as a risk factor for implant loss with a hazard ratio of 3.32 (1.36-8.09). Retrospective analysis of comorbidity factors and clinical outcomes revealed risk factors for postoperative complications after BAHI surgery.