Background: We studied the cumulative incidence and predictors of return to active status and transplant of obese kidney candidates designated “temporarily inactive” (status 7) due to a "weight inappropriate for transplant” (reason 9) on the United Network for Organ Sharing (UNOS) waiting list.

Methods: All adult kidney candidates in the OPTN/UNOS database with an initial registration between 2006-2010, body mass index (BMI)≥30 kg/m², and designation of status 7 due to reason 9 within 90 days of registration were included. The cumulative incidence of return to active status, transplant, death, and delisting was described using Fine and Gray competing risks regression. Cause-specific hazards of return to active status and transplant were calculated using Cox proportional hazards models.

Results: Among 1557 waitlisted candidates, the cumulative incidence of return to active status at 6 years was 48%, for transplant was 23%, for death was 16%, and for delisting was 21%. Only 15% remained inactive at 6 years (fig. 1). The strongest predictor of failure to return to active status was BMI at registration. Each BMI category increase was associated with a lower hazard of return to active status (P for trend<0.001). Female gender, race, diabetes, and dialysis at registration were also associated with a failure to return to active status (table 1).

Conclusion: Only 48% of reason 9 obese kidney candidates achieved active status within 6 years of registration, with the majority activated within 3 years. Of those not activated, most died or delisted, suggesting that more precise prediction tools should be developed to identify obese candidates who will realistically attain a weight appropriate for transplant.

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