Table 2. 12-month health care costs and utilization, Lyme disease and control groups.
| (I) Unadjusted mean during 12-month study period, Lyme disease group * , † | (II) Unadjusted mean during 12-month study period, control group † , ‡ | (III) Welch’s t-test (of difference in means) | (IV) Adjusted impact of Lyme disease diagnosis on 12-month health care costs and utilization, (Robust SE) | ||
|---|---|---|---|---|---|
| Adjusted impact of Lyme disease diagnosis on 12-month health care costs (Robust SE) || | |||||
| Total cost | $ 8,205 | $ 4,421 | p<.001 | $ 2,968 (81.9)*** | |
| Inpatient cost | $ 1,710 | $ 1,038 | p<.001 | $ 230 (55.9)*** | |
| Pharmacy cost | $ 1,525 | $ 826 | p<.001 | $ 612 (16.6)*** | |
| Outpatient cost | $ 4,969 | $ 2,557 | p<.001 | $ 2,125 (47.4)*** | |
| Cost by outpatient category: | Evaluation and Management | $ 904 | $ 412 | p<.001 | $ 464 (4.1)*** |
| Medicine § | $ 622 | $ 326 | p<.001 | $ 275 (7.4)*** | |
| Pathology Laboratory | $ 487 | $ 140 | p<.001 | $ 332 (4.4)*** | |
| Radiology | $ 575 | $ 244 | p<.001 | $ 294 (9.0)*** | |
| Anesthesiology | $ 100 | $ 58 | p<.001 | $ 38 (1.6)*** | |
| Surgery | $ 605 | $ 328 | p<.001 | $ 255 (8.4)*** | |
| Other (none of the above) | $ 1,677 | $ 1,048 | p<.001 | $ 467 (36.2)*** | |
| Adjusted impact of Lyme disease diagnosis on 12-month health care utilization, (Robust SE) ¶ | |||||
| Outpatient management and evaluation visits | 6.97 | 3.65 | p<.001 | 1.87 (0.008)*** | |
| Emergency visits | 0.35 | 0.20 | p<.001 | 1.71 (0.020)*** | |
*** statistically significant at p<.001 level,
* Lyme disease sample includes only those persons with a test order and antibiotic treatment within 30 days of the test order, a diagnosis and antibiotic treatment within 30 days of the diagnosis, or a diagnosis, test order and antibiotic treatment within 30 days. The Lyme disease sample includes only those with 18 consecutive months of enrollment, including a 6-month “clean period” of enrollment prior to Lyme disease episode in which they were neither diagnosed with nor tested for Lyme disease.
† Lyme disease and control samples are restricted to persons under 65 years of age, in commercial health insurance plans.
‡ Controls were matched to Lyme disease cases on age, sex, region, payer and enrollment year. Control group includes only those with 18 consecutive months of enrollment in a commercial health insurance plan. Control group was restricted to persons with outpatient costs greater than $0.
§ Medicine includes acupuncture, home health, home infusion and other special services, procedures and reports.
|| Adjusted impact calculations based on GLM regression analysis using the Huber/White sandwich estimator of variance and adjusting for year, region, age, and sex, and controlling for 44 high-cost conditions
¶ Adjusted ratio calculations for outpatient and emergency visits are based on negative binomial regression analysis using the Huber/White sandwich estimator of variance and adjusting for year, region, age, and sex, and controlling for 44 high-cost conditions.