Cervical re-explorations and proxy survival following parathyroidectomy for primary hyperparathyroidism using Australian administrative data

Background: Administrative data may have utility in the impartial assessment of surgical outcomes and rare events. We have used a publicly available sample of the Australian pharmaceutical and health service provision (medical benefits scheme) databases to assess outcomes following parathyroidectomy for primary hyperparathyroidism (PHP). Methods: A cohort study using linked pharmaceutical and medical benefits schemes data was performed covering the period 1993–2014. Procedure codes identified participants undergoing parathyroidectomy for PHP and subsequent cervical re-exploration surgery (CRX), and the last service date used as a proxy for survival. Time to CRX and survival were modelled using Kaplan–Meier analysis. Demographic data and the era of parathyroid surgery were managed as covariates for Cox regression survival analyses. Results: A total of 2165 persons undergoing parathyroidectomy for PHP were identified. Median follow-up was 5.3 years (range 0.2–22). The annual number of parathyroidectomies for PHP increased gradually; 72 individuals underwent CRX (3.3%). The median time to CRX was 152 days (confidence interval 0–396) in 2000–2004 reducing to 47 days (confidence interval 15–78) for the period 2010–2014 (log-rank P = 0.027). The proportion of persons requiring CRX reduced over time from 6.1% in 1997 to 2.1% in 2012 (r² = 0.5817, P = 0.023). Overall median survival (24.6 years) was poorer when compared with age matched controls (log-rank P = 0.025) but was not associated with CRX or gender. Conclusion: Administrative data can be used for the assessment of surgical outcomes and may be useful for comparisons of surgical performance, and the appraisal of infrequent events. CRX rates following parathyroidectomy for PHP are improving in Australia.