Validation of the Patient-Reported Outcomes Measurement Information System (PROMIS) physical function questionnaire in late-onset Pompe disease using PROPEL phase 3 data.

BACKGROUND

The construct validity and interpretation of the Patient-Reported Outcome Measurement Information System (PROMIS) Physical Function short form 20a (PF20a) questionnaire were evaluated for patients with late-onset Pompe disease (LOPD), a rare, autosomal recessive, progressive neuromuscular disorder treatable by enzyme replacement therapy (ERT).

METHODS

In the phase 3 PROPEL study, adults with LOPD underwent testing of physical functioning and had PRO measurements at baseline and at weeks 12, 26, 38, and 52 while receiving experimental or standard-of-care ERT. All patients were pooled for analyses, without comparisons between treatment groups. Associations and correlations between PROMIS PF20a scores and the 6-minute walk distance (6MWD), % predicted forced vital capacity (FVC), manual muscle test (MMT) of the lower extremities, Gait, Stairs, Gowers' maneuver, Chair (GSGC) score, and Rasch-built Pompe-specific Activity (R-PAct) scale were evaluated by calculating regression coefficients in linear regression models and Pearson correlation coefficients (R); patients' age, sex, race, ERT prior to study, body mass index, and study treatment were included as covariables. The minimal clinically important difference (MCID) of PROMIS PF20a was determined using distribution- and anchor-based methods.

RESULTS

123 patients received at least 1 dose of ERT. In multivariable analyses, PROMIS PF20a scores had strong correlations with R-PAct scores (R = 0.83 at baseline and R = 0.67 when evaluating changes between baseline and 52 weeks) and moderate correlations with the 6MWD (R = 0.57 at baseline and R = 0.48 when evaluating changes between baseline and 52 weeks). Moderate correlations were also observed between PROMIS PF20a and MMT (R = 0.54), GSGC (R=-0.51), and FVC (R = 0.48) at baseline. In multivariable linear regression models, associations were significant between PROMIS PF20a and 6MWD (P = 0.0006), MMT (P = 0.0034), GSGC (P = 0.0278), and R-PAct (P < 0.0001) at baseline, between PROMIS PF20a and 6MWD (P < 0.0001), FVC (P = 0.0490), and R-PAct (P < 0.0001) when combining all measurements, and between PF20a and 6MWD (P = 0.0016) and R-PAct (P = 0.0001) when evaluating changes in scores between baseline and 52 weeks. The anchor-based and distribution-based MCID for a clinically important improvement for PROMIS PF20a were 2.4 and 4.2, respectively.

CONCLUSIONS

PROMIS PF20a has validity as an instrument both to measure and to longitudinally follow physical function in patients with LOPD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03729362. Registered 2 November 2018, https://www.

CLINICALTRIALS

gov/search?term=NCT03729362 .