Potential Impact of Opportunistic CT for Closing Diagnosis Gaps in Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is underdiagnosed. Opportunistic assessment for enlarged parathyroid glands on routine CT examinations is a proposed approach to improve diagnosis. However, the proportion of at-risk patients with a relevant CT is unknown. We aimed to determine the proportion of individuals with hypercalcemia untested for PHPT who had CT examinations on which opportunistic screening could have been performed and to assess characteristics associated with imaging availability.

This retrospective study included adults with hypercalcemia untested for PHPT within our health system between January 2018 and December 2022. Each patient was classified as imaging available versus unavailable based on the presence of contrast-enhanced CTs including the parathyroid region performed between January 2013 and December 2022. Characteristics of these groups were compared.

The sample comprised 10,702 patients (mean age, 57 years; 6,422 female and 4,280 male patients) with CTs available in 1,318 (12.3%). Characteristics associated with the greatest odds of available CT were Charlson Comorbidity Index ≥ 5 (odds ratio [OR] 5.29, P < .0001), death during the study period (OR 2.31, P < .0001), fatigue (OR 1.90, P < .0001), weakness (OR 1.60, P < .0001), and calcium > 12.0 mg/dL (OR 1.44, P < .0001). Characteristics associated with the lowest odds of available CT were age ≥ 85 years (OR 0.27, P < .0001), age < 35 years (OR 0.58, P < .0001), and chronic kidney disease (OR 0.64, P < .0001).

More than 12% of patients with hypercalcemia who were untested for PHPT had at least one CT that could have been used to opportunistically assess the parathyroid glands. Patients with imaging tended to have more comorbidities than those without.