Objective: To examine trends in the frequency and quality of surgery for primary hyperparathyroidism (PHPT) in California during the period of 1999 to 2008.
Background: The quality of surgery for PHPT can be measured by the complication rate and the success rate of surgery. A fraction of patients with failed initial surgery undergo reoperation.
Methods: Data on patients undergoing parathyroidectomy (PTx) were obtained from the California Office of Statewide Health Planning and Development. Renal transplant recipients and dialysis patients were excluded. Hospitals were categorized by case volume: Very low: 1 to 4 operations annually; Low: 5 to 9; Medium, 10 to 19; High: 20 to 49; Very high: 50 or more. Complication rates and the percentage of cases requiring reoperation were analyzed.
Results: A total of 17,082 cases were studied. Annual case volume grew from 990 to 2746 (177% increase) over the study period, corresponding to a 147% increase in the per capita PTx rate. The proportion of cases performed by very high-volume hospitals increased from 6.4% to 20.5% (P < 0.001). The overall complication rate declined from 8.7% to 3.8% (P < 0.001). Complication rates were inversely related to hospital volume (very high volume, 3.9% vs very low volume, 5.2%, P < 0.05). Reoperation was performed in 363 patients (2.1%). The reoperation rate increased from 0.91% to 2.73% during the study period (P < 0.01). The reoperation rate was inversely and nonlinearly related to hospital volume, as described by the equation % reoperation = 100/(total hospital case volume).
Conclusions: Surgery for PHPT has grown safer and more common over time. High-volume centers have lower rates of complication and reoperation.