Endocrine Abstracts

Objective: Pituitary diseases cause a wide range of local and systemic symptoms and severely affect patients’ health-related quality of life (HRQoL), which can be monitored using both disease-specific and generic questionnaires. The most frequently used generic HRQoL questionnaire is the Short Form-36 (SF-36), generating a mental (MCS) and physical component score (PCS). The shorter 12-item version (SF-12) can improve efficiency of patient monitoring and outcome measurement and reduce the burden for patients. This study therefore aimed to determine whether the SF-12 can be used instead of the SF-36 in pituitary care.

Study design and methods: Data of a longitudinal perioperative cohort study (August 2016 – December 2018) were used, comprising 103 adult patients endoscopically operated for a pituitary adenoma with 6 months follow-up. A chronic care cross-sectional cohort study in 431 adults with a pituitary tumor was analyzed in parallel. Both studies were conducted in a tertiary referral center in the Netherlands. The PCS and MCS of SF-36 and SF-12 were measured preoperatively, and 6 weeks and 6 months postoperatively. Agreement between questionnaires on each timepoint and over time was assessed with intraclass correlation coefficients (ICC) and Bland-Altman plots, presenting the limits of agreement (95% of the observed values). Linear regression analysis was used to determine the association of baseline factors with a large individual difference (>5 points) between SF-36 and SF-12.

Results: For PCS, ICCs were 0.590 preoperatively, 0.548 at 6 weeks and 0.622 at 6 months. ICCs for MCS were higher, respectively 0.952, 0.948, and 0.943. At the same time points, mean differences between SF-36 and SF-12 were 4.1, 4.7 and 5.9 points for PCS, and 1.3, 1.5, and 1.7 points for MCS. Limits of agreement for change (6 months vs preoperatively) were –14.0 to 16.9 for PCS and -7.8 to 8.7 for MCS. Similar results were found in the cross-sectional cohort. No baseline factors were consistently associated with a large individual difference between the SF-36 and SF-12.

Conclusions: The SF-12 can reliably reproduce the MCS in pituitary patients, but PCS of SF-36 and SF-12 is less well correlated. Moreover, wide limits of agreement show that individual differences between the SF-36 and SF-12 can be large. The SF-36, that also offers the advantage of generating HRQoL domain scores, is therefore recommended for use in pituitary care. Further strategies to reduce the number of questions in both validated generic and disease-specific HRQoL questionnaires must be evaluated for this patient population.