Smoking status and health care costs in the perioperative period: a population-based study

Abstract

Importance: Cigarette smoking adds an estimated $100 billion in annual incremental direct health care costs nationwide. Cigarette smoking increases complication risk in surgical patients, but the potential effects of smoking status on perioperative health care costs are unclear.

Objective: To test the hypothesis that current and former smoking at the time of admission for inpatient surgery, compared with never smoking, are independently associated with higher incremental health care costs for the surgical episode and the first year after hospital discharge.

Design, setting, and participants: This population-based, propensity-matched cohort study, with cohort membership based on smoking status (current smokers, former smokers, and never smokers) was performed at Mayo Clinic in Rochester (a tertiary care center) and included patients at least 18 years old who lived in Olmsted County, Minnesota, for at least 1 year before and after the index surgery.

Exposure: Undergoing an inpatient surgical procedure at Mayo Clinic hospitals between April 1, 2008, and December 31, 2009.

Main outcomes and measures: Total costs during the index surgical episode and 1 year after hospital discharge, with the latter standardized as costs per month. Costs were measured using the Olmsted County Healthcare Expenditure and Utilization Database, a claims-based database including information on medical resource use, associated charges, and estimated economic costs for patients receiving care at the 2 medical groups (Mayo Clinic and Olmsted Medical Center) that provide most medical services within Olmsted County, Minnesota.

Results: Propensity matching resulted in 678 matched pairs in the current vs never smoker grouping and 945 pairs in the former vs never smoker grouping. Compared with never smokers, adjusted costs for the index hospitalization did not differ significantly for current or former smokers. However, the adjusted costs in the year after hospitalization were significantly higher for current and former smokers based on regression analysis (predicted monthly difference of $400 [95% CI, $131-$669] and $273 [95% CI, $56-$490] for current and former smokers, respectively).

Conclusions and relevance: Compared with never smokers, health care costs during the first year after hospital discharge for an inpatient surgical procedure are higher in both former and current smokers, although the cost of the index hospitalization is not affected by smoking status.

Figure. Study Time Frame, Including Baseline, Index Surgical Episode, and Follow-up

The index surgical episode was defined as starting 7 days before index hospital admission and ending at hospital discharge. This period was chosen so that costs associated with hospital admission (eg, preoperative evaluation and emergency department admission) were included as part of the index costs. The baseline period included 1 year before the start of the index episode. Patients were followed up for 1 year after the end of the index episode. Patients who had an inpatient surgical procedure within 1 year before the index date, died during the index hospitalization, or declined research authorization as per Minnesota statutes were excluded from study.