A Revised Estimate of Costs Associated With Routine Preoperative Testing in Medicare Cataract Patients With a Procedure-Specific Indicator

Abstract

Importance: Routine preoperative medical testing is not recommended for patients undergoing low-risk surgery, but testing is common before surgery. A 30-day preoperative testing window is conventionally used for study purposes; however, the extent of routine testing that occurs prior to that point is unknown.

Objective: To improve on existing cost estimates by identifying all routine preoperative testing that takes place after the decision is made to perform cataract surgery.

Design, setting, and participants: This cross-sectional study assessed preoperative care in a 50% sample of Medicare beneficiaries older than 66 years who underwent ambulatory cataract surgery in 2011. Data analysis was completed from March 2016 to October 2017.

Main outcomes and measures: Using ocular biometry as a procedure-specific indicator to mark the start of the routine preoperative testing window, we measured testing rates in the interval between ocular biometry and cataract surgery and compared this with testing rates in the 6 months preceding biometry. We estimated the total cost of testing that occurred between biometry and cataract surgery.

Results: A total of 440 857 patients underwent cataract surgery. A total of 423 710 (96.1%) had an ocular biometry claim before index surgery, of whom 264 514 (60.0%) were female; the mean (SD) age of the cohort was 76.1 (6.2) years. A total of 111 998 (25.4%) underwent surgery more than 30 days after biometry. Among patients with a biometry claim, the mean number of tests/patient/month increased from 1.1 in the baseline period to 1.7 in the interval between biometry and cataract surgery. Although preoperative testing peaked in all patients in the 30 days preceding surgery (1.8 tests/patient/month), the subset of patients with no overlap between postbiometry and presurgery periods experienced increased testing rates to 1.8 tests per patient per month in the 30 days after biometry, regardless of the elapsed time between biometry and surgery. The total estimated cost of routine preoperative testing in the full cohort was $22.7 million; we estimate that routine preoperative testing costs Medicare up to $45.4 million annually.

Conclusions and relevance: In this study of Medicare beneficiaries, routine preoperative medical testing occurs more often and is costlier than has been reported previously. Extra costs are attributable to testing that occurs prior to the 30-day window preceding surgery. As a cost-cutting measure, routine preoperative medical testing should be avoided in patients with cataracts throughout the interval between ocular biometry and cataract surgery.

Figure 1.. Relationship Between Cataract Surgery Date and Ocular Biometry Date

Among patients with a biometry claim, 75% had cataract surgery within 30 days after biometry, 20% had surgery between 31 and 90 days after biometry, and 5% had surgery more than 90 days after biometry. Patients with more than 120 days between biometry and surgery are not shown. The periodic pattern of biometry claims relative to surgery claims reflects the typical weekly intervals between the ophthalmology office visit and cataract surgery date.

Figure 2.. Rate of Preoperative Testing in Patients in the Interval Between Biometry and Surgery

Preoperative testing rates in the months after ocular biometry and before cataract surgery were spliced to create a single graph of preoperative testing rates over time in relation to biometry and surgery. A, Patients with 6 months between biometry and surgery (n = 2133); B, patients with 9 months between biometry and surgery (n = 1136); C, patients with a Charlson comorbidity score of 0, an absence of preoperative testing in the 6 months prior to biometry, and a greater than 90-day interval between biometry and surgery (n = 961). The X-axis labels refer to the date of ocular biometry (B) or cataract surgery (S).

Figure 3.. Rate of Preoperative Testing in Patients Having Cataract Surgery More Than 30 Days After Ocular Biometry, Stratified by Interval in Months Between Biometry and Surgery

This figure was created using data from all patients with greater than 30 days between biometry and surgery claim dates (n = 107 812). More prebiometry data were available for patients with fewer months between biometry and surgery because of the shorter interval between biometry and surgery claim dates. For each cohort of patients, the first spike from the left represents preoperative testing that occurred in the month after ocular biometry. The second spike represents preoperative testing that occurred in the month preceding cataract surgery. The x-axis labels are approximate representations of the timing of postbiometry testing in reference to the date of surgery. Exact labeling of postbiometry periods was impossible on this single graph given the wide variation in time between biometry and surgery represented on the graph. The x-axis labels are in reference to the date of cataract surgery (S).

Figure 4.. Frequency and Cost of Routine Preoperative Testing, Grouped by Preoperative Testing Period

The category “1 year prior to biometry” represents a baseline period of equal length starting 1 year prior to the extended preoperative testing window (ie, the time between the dates of the ocular biometry claim and the cataract surgery claim). For the 1.5% of patients whose time from biometry to surgery exceeded the number of baseline months available for direct comparison, we adjusted our frequency and cost calculations to reflect the ratio of the number of months included in the biometry to surgery period vs the number of months included in the shorter baseline period.