Comparison of Health State Utility Measures in Patients With Head and Neck Cancer.

IMPORTANCE

Accurate measurement of health state utilities (HU) is the cornerstone for cost-utility analyses and the valuation of quality of life for given health states. Current indirect methods of HU derivation lack face validity for patients with head and neck cancer. The appropriateness of these measures compared with direct methods, such as the standard gamble (SG), time trade-off (TTO), and visual analog scale (VAS), have not been assessed in this patient population.

OBJECTIVE

To assess the convergent and construct validities of 5 different HU derivation methods in patients with head and neck cancer.

DESIGN, SETTING, AND PARTICIPANTS: In a cross-sectional study, we recruited 100 consecutive patients with squamous cell carcinoma of the upper aerodigestive tract treated in the outpatient surgical oncology clinics of the Princess Margaret Cancer Centre from August 1 through October 31, 2014. We enrolled patients with a minimum of 3 months of follow-up after completion of treatment and no evidence of recurrent or metastatic disease. Participants completed SG, TTO, and VAS exercises, the EuroQoL instrument (EQ-5D), and the Health Utilities Index Mark 3 (HUI3) questionnaire. Data analysis was performed November 1 through December 15, 2014.

EXPOSURES

Head and neck cancer and HU measures.

MAIN OUTCOMES AND MEASURES

We assessed convergent validity of the 5 HU instruments through Spearman rank order correlation assessment. We determined construct validity through a priori hypotheses relating HU scores with clinical indexes of disease severity.

RESULTS

The SG and TTO measures generated higher mean (SD) utility scores (0.91 [0.17] and 0.94 [0.14], respectively) than the VAS, EQ-5D, and HUI3 (0.76 [0.19], 0.82 [0.18], and 0.75 [025], respectively) (P < .001). The maximum score of 1.0 was reported in 60 of 99 cases (61%) for the SG and 75 of 99 cases (76%) for the TTO (a significant ceiling effect), in contrast to 5 of 99 cases (5%) for the VAS, 29 of 99 cases (29%) for the EQ-5D, and 6 of 99 cases (6%) for the HUI3. The VAS showed strong correlations with the EQ-5D (ρ = 0.63 [P < .001]) and HUI3 (ρ = 0.50 [P < .001]), and the HUI3 strongly correlated with the EQ-5D (ρ = 0.67 [P < .001]), whereas the SG and TTO generally correlated poorly with other HU measures (ρ range, 0.19-0.29) and with one another (ρ = 0.21 [P < .001]). The VAS, EQ-5D, and HUI3 were able to discriminate between participants who underwent salvage surgery compared with those who underwent primary surgery (mean [SD] utility scores, 0.48 [0.13] vs 0.76 [0.20] [P = .006], 0.62 [0.17] vs 0.83 [0.19] [P = .004], and 0.37 [0.29] vs 0.78 [0.22] [P = .004], respectively). Mean EQ-5D utility scores monotonically increased over time since completion of treatment (0.26 [P = .01]). The HUI3 yielded lower utility values for participants with laryngeal cancer (mean [SD], 0.59 [0.29]). The SG and TTO measures frequently generated utility scores that contradicted our hypothesized expectations.

CONCLUSIONS AND RELEVANCE

Indirect HU measures may be more reflective of the health status of patients with head and neck cancer than direct measures. Current instruments lack face validity for attributes germane to this population.