Estimating Health Utility in Patients Presenting for Spine Surgery Using Patient-reported Outcomes Measurement Information System (PROMIS) Health Domains

Abstract

Study Design. 

Prospective cohort study.

Objective. 

To evaluate whether Patient-Reported Outcomes Measurement Information System (PROMIS) health domains can effectively estimate health utility index values for patients presenting for spine surgery.

Summary of Background Data. 

Stable estimates of health utility are required to determine cost-effectiveness of spine surgery. There are no established methods to estimate health utility using PROMIS.

Methods. 

We enrolled 439 patients with spine disease (mean age, 54 ± 18 yrs) presenting for surgery and assessed their health using the Medical Outcomes Study Short Form-12, version 2 (SF-12v2) and PROMIS domains. Standard health utility values were estimated from the SF-12v2. Participants were randomly assigned to derivation or validation cohort. In the derivation cohort, health utility values were estimated as a function of PROMIS domains using regression models. Model fit statistics determined the most parsimonious health utility estimation equation (HEE). In the validation cohort, values were calculated using the HEE. Estimated health utility values were correlated with SF-12v2-derived health utility values.

Results. 

Mean preoperative health utility was 0.492 ± 0.008 and was similar between the two cohorts. All PROMIS health domains were significantly associated with health utility except Anxiety (P = 0.830) and Sleep Disturbance (P = 0.818). The final HEE was:

Health Utility (est) = 0.70742 – 0.00471 × Pain + 0.00647 × Physical function – 0.00316 × Fatigue – 0.00214 × Depression + 0.00317 × Satisfaction with Participation in Social Roles.

The estimation model accounted for 74% of observed variation in health utility. In the validation sample, mean health utility was 0.5033 ± 0.1684 and estimated health utility was 0.4966 ± 0.1342 (P = 0.401). These measures were strongly correlated (rho = 0.834).

Conclusion. 

Our results indicate that PROMIS provides a reasonable estimate of health utility in adults presenting for lumbar or cervical spine surgery.

Level of Evidence: 1

In Brief

Despite the increasing use of PROMIS in healthcare, to our knowledge, no previous studies have attempted to estimate a health utility index using PROMIS in patients undergoing spine surgery. Our results show that PROMIS is a reliable tool that may be used to estimate reliable quality-adjusted life-years in spine surgery patients.