Preoperative consultations for medicare patients undergoing cataract surgery

Abstract

Importance: Low-risk elective surgical procedures are common, but there are no clear guidelines for when preoperative consultations are required. Such consultations may therefore represent a substantial discretionary service.

Objective: To assess temporal trends, explanatory factors, and geographic variation for preoperative consultation in Medicare beneficiaries undergoing cataract surgery, a common low-risk elective procedure.

Design, setting, and participants: Cohort study using a 5% national random sample of Medicare part B claims data including a cohort of 556,637 patients 66 years or older who underwent cataract surgery from 1995 to 2006. Temporal trends in consultations were evaluated within this entire cohort, whereas explanatory factors and geographic variation were evaluated within the 89,817 individuals who underwent surgery from 2005 to 2006.

Main outcomes and measures: Separately billed preoperative consultations (performed by family practitioners, general internists, pulmonologists, endocrinologists, cardiologists, nurse practitioners, or anesthesiologists) within 42 days before index surgery.

Results: The frequency of preoperative consultations increased from 11.3% in 1998 to 18.4% in 2006. Among individuals who underwent surgery in 2005 to 2006, hierarchical logistic regression modeling found several factors to be associated with preoperative consultation, including increased age (75-84 years vs 66-74 years: adjusted odds ratio [AOR], 1.09 [95% CI, 1.04-1.13]), race (African American race vs other: AOR, 0.71 [95% CI, 0.65-0.78]), urban residence (urban residence vs isolated rural town: AOR, 1.64 [95% CI, 1.49-1.81]), facility type (outpatient hospital vs ambulatory surgical facility: AOR, 1.10 [95% CI, 1.05-1.15]), anesthesia provider (anesthesiologist vs non-medically directed nurse anesthetist: AOR, 1.16 [95% CI, 1.10-1.24), and geographic region (Northeast vs South: AOR, 3.09 [95% CI, 2.33-4.10]). The burden of comorbidity was associated with consultation, but the effect size was small (<10%). Variation in frequency of consultation across hospital referral regions was substantial (median [range], 12% [0-69%]), even after accounting for differences in patient-level, anesthesia provider-level, and facility-level characteristics.

Conclusions and relevance: Between 1995 and 2006, the frequency of preoperative consultation for cataract surgery increased substantially. Referrals for consultation seem to be primarily driven by nonmedical factors, with substantial geographic variation.

Figure 1. Adjusted Probability of Preoperative Consultation by Calendar Year

Circles represent the adjusted probability of preoperative consultation by calendar year, and vertical bars denote 95% CIs computed using robust variance estimation.

Figure 2. Distribution of Preoperative Consultations in the 42 Days Before Surgery

Frequency distribution of consultations during the 42-day preoperative period for cataract surgery procedures in 2005 to 2006. A multimodal distribution is observed, with peaks at weekly intervals. The highest frequency occurred on preoperative day 7.

Figure 3. Variation in Frequency of Consultation Across Hospital Referral Regions

Points represent unadjusted proportions of individuals undergoing consultation before cataract surgery across 306 hospital referral regions (HRRs) during 2005 to 2006. Vertical lines represent exact binomial 95% CIs. The dotted horizontal line denotes the overall proportion undergoing consultation (17.8%). The HRRs are ordered along the x-axis from lowest to highest frequency of consultations.