The risk paradox: use of elective cholecystectomy in older patients is independent of their risk of developing complications

Abstract

Background: We recently developed and validated a prognostic model that accurately predicts the 2-year risk of emergent gallstone-related hospitalization in older patients presenting with symptomatic gallstones.

Study design: We used 100% Texas Medicare data (2000 to 2011) to identify patients aged 66 years and older with an initial episode of symptomatic gallstones not requiring emergency hospitalization. At presentation, we calculated each patient's risk of 2-year gallstone-related emergent hospitalization using the previously validated model. Patients were placed into the following risk groups based on model estimates: <30%, 30% to <60%, and ≥ 60%. Within each risk group, we calculated the percent of elective cholecystectomies (≤ 2.5 months from initial episode) performed.

Results: In all, 161,568 patients had an episode of symptomatic gallstones. Mean age was 76.5 ± 7.3 years and 59.9% were female. The 2-year risk of gallstone-related hospitalizations increased from 15.9% to 41.5% to 65.2% across risk groups. For the overall cohort, 22.3% in the low-risk group, 20.9% in the moderate-risk group, and 23.2% in the high-risk group underwent elective cholecystectomy in the 2.5 months after the initial symptomatic episode. In patients with no comorbidities, elective cholecystectomy rates decreased from 34.2% in the low-risk group to 26.7% in the high-risk group. Of patients who did not undergo cholecystectomy, only 9.5% were seen by a surgeon in the 2.5 months after the initial episode.

Conclusions: The risk of recurrent acute biliary symptoms requiring hospitalization has no influence, or even a paradoxical negative influence, on the decision to perform elective cholecystectomy after an initial symptomatic episode. Translation of the risk prediction model into clinical practice can better align treatment with risk and improve outcomes in older patients with symptomatic gallstones.

Figure 1

Cohort selection. Inclusion criteria: 1) Symptomatic cholelithiasis defined by a) Primary diagnosis of ICD-9-CM code 574 of 575 or b) Primary diagnosis of acute pancreatitis (577.0) and a secondary diagnosis of 574 or 575; 2) Patients age 66 and older; 3) Patients with Medicare Part A and Part B 1 year before and 2 years after the initial episode; 4) Patients not admitted to the hospital on the incident episode; and 5) Patients who underwent CT and/or US in the month before or after diagnosis were included. US, ultrasound.

Figure 2

Sample of risk calculation using the PREOP-Gallstones model nomogram. To use the nomogram, a vertical line is drawn from each factor to the corresponding position on the “Points” line. Points are summed for each factor and a line is drawn (downward arrow) from this position on the “Points” line to the “Emergent Visit Probability” lines to determine a patient's 12-month and 24-month risk for developing emergent gallstone-related complications.

Figure 3

Two-year gallstone-related hospitalization rates in the 125,601 patients who did not undergo elective cholecystectomy in the 2.5 months after the incident symptomatic episode. The black bars represent the actual rates and the gray bars represent the cumulative incidence censored for patient deaths and elective cholecystectomy, when patients were no longer at risk for emergent gallstone-related hospitalization.

Figure 4

Percentage of patients undergoing cholecystectomy by risk group (<30%, 30-60%, >60%). The black bars represent the percentage of the overall cohort (N=161,568) and the gray bars represent the percentage of the 25,633 patients with no comorbidities undergoing cholecystectomy.