Introduction
The Pituitary Outcome Score (POS) is a patient-reported outcome measure (PROM) developed to assess patient-perceived symptoms and quality of life before and after transsphenoidal surgery for pituitary adenoma. First introduced in 2022 by Elika Karvandi and others, the POS has since become an indispensable tool in endocrine neurosurgery and pituitary research. Consequently, its primary validation study has amassed over 10 citations, underscoring its significant impact and widespread adoption within the neurosurgical and endocrinology research community.
This article serves as an expert guide, meticulously detailing the POS's key features, clinical and research applications, and psychometric value. Ultimately, it provides researchers and clinicians with the necessary insights for effectively incorporating this powerful instrument into their practice and studies.
Key Features of the Pituitary Outcome Score (POS)
Purpose and Use
The primary purpose of the POS is to assess patient-perceived symptoms and quality of life before and after transsphenoidal surgery for pituitary adenoma. As a patient-reported outcome measure (PROM), it provides clinicians and researchers with a standardized tool to evaluate both general health-related quality of life and surgery-related symptom burden in this specific patient population. Consequently, this enables effective monitoring of changes over time, from preoperative baseline through postoperative recovery.
Target Population
The POS is specifically validated for adults aged 18 years and older undergoing transsphenoidal surgery for pituitary adenoma. This includes:
Young Adults (18-24 years)Middle-Aged Adults (25-44 years)Older Adults (45-64 years)Seniors (65+ years)Structure
The POS consists of 25 items divided into four distinct subscales, each measuring a unique aspect of patient health:
EQ-5D-5L-QoL Subscale: Evaluates five dimensions of health status: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression.Visual Symptoms Subscale: Assesses the frequency and functional impact of visual disturbances, including double vision and vision-related interference with daily activities.Endocrine Symptoms Subscale: Addresses hormone-related complaints such as fatigue, libido issues, appetite and weight changes, memory difficulties, sleep problems, and mood swings.Nasal Symptoms Subscale: Focuses on sinonasal complaints linked to the transsphenoidal approach, including nasal congestion, altered smell or taste, and headaches.Importantly, the study does not recommend a global total POS score. Therefore, you should interpret each subscale independently.
Scoring Method
The POS employs ordinal response categories (Likert scales with 4–7 categories per item). Specifically, you sum item responses within each subscale to generate raw subscale scores.
Critically, the original validation study does not define or recommend a global total POS score. Therefore, each subscale must be interpreted independently. Researchers and clinicians should focus on subscale scores and their changes over time (pre- versus post-operation) rather than calculating a composite total.
It is important to note that the original development and validation study did not define diagnostic cut-off values or severity categories for any of the POS subscales. Interpretation is based on comparing subscale scores across different time points to assess clinical improvement or decline following transsphenoidal surgery for pituitary adenoma.
Administration Format
The POS is efficient, typically taking only 10 to 15 minutes to complete. Moreover, healthcare teams can administer the questionnaire via:
Paper-based formsDigital (online) platformsIn-person interviewPhone/Video callNotably, no special training is required, as it is a self-administered questionnaire.
Applications of the Pituitary Outcome Score (POS)
The POS is a versatile tool with several key applications in clinical practice and research:
Monitoring: It allows clinicians to track a patient’s symptom burden and quality of life changes over time, especially before and after surgery.Research: It serves as a reliable and valid endpoint for clinical trials and observational studies focused on surgical outcomes for pituitary adenoma.Languages and availability
Currently, the POS is available only in English. The original validation study does not report any translated or culturally adapted versions at this time.
Regarding availability and licensing, the POS article is published under a Creative Commons (CC BY 4.0) license, which allows for sharing and adaptation with proper attribution. However, it is critical to note that the POS incorporates EQ-5D-5L content, which requires separate registration and licensing through the EuroQol Research Foundation. Therefore, permission is needed for any use of the instrument that includes the EQ-5D-5L components.
Researchers and clinicians interested in using the POS should contact the EuroQol Research Foundation for the necessary license before incorporating this instrument into their practice or studies.
Reliability and Validity
The psychometric soundness of the POS is well-documented in its original validation study. For instance, the POS demonstrates high reliability and validity, with Cronbach’s alpha values confirming excellent internal consistency:
EQ-5D-5L-QoL: 835Visual Symptoms: 759Endocrine Symptoms: 910Nasal Symptoms: 634Additionally, the instrument shows excellent test-retest reliability within its original single-center validation study.
The Original Validation Study linkLimitations and Considerations
Despite its strengths, the POS has several limitations:
Self-report measure: Responses can be influenced by a patient’s subjective perception or social desirability bias.Length (Too Long): Some patients may find the 25-item questionnaire lengthy.Language Barriers: Currently, the POS is only available in English.Limited Validation Studies: Independent external validation has not yet been reported.Social Desirability Bias: Respondents may answer in a way they perceive to be socially acceptable rather than reporting their actual symptoms and experiences, potentially biasing the results.Other Versions And Related Questionnaires
Researchers should be aware of other questionnaires that are similar or complementary to the POS:
Leiden Bother and Needs Questionnaire for patients with pituitary diseaseAnterior Skull Base Questionnaire (ASBQ)Currently, no other versions (such as short forms or expanded adaptations) of the POS are available.
Additional Resources
The Original Validation Study linkYou can access the questionnaire as a PDF through this linkLeiden Bother and Needs Questionnaire for patients with pituitary disease linkFor inquiries, contact Elika Karvandi, the first author of the questionnaire: eek34@cam.ac.ukFor additional POS resources, consult Springer NatureFrequently Asked Questions (FAQ)
1. Who can use the Pituitary Outcome Score (POS)?
Clinicians, researchers, and healthcare providers use the POS for adults aged 18 and older who are undergoing transsphenoidal surgery for pituitary adenoma.
2. How long does it take to complete the POS?
Patients typically need 10 to 15 minutes to complete all 25 items, making it feasible for routine clinical use.
3. How is the POS administered?
Healthcare teams can administer the questionnaire via paper-based forms, digital platforms, in-person interviews, or phone/video calls.
4. Is there any cost to using the POS?
The POS article is free under CC BY 4.0. However, because it incorporates EQ-5D-5L content, you must register and obtain a license from the EuroQol Research Foundation separately. Therefore, permission is needed.
5. What is the cut-off score for the POS?
The study defines no cut-off scores. Instead, interpretation relies on subscale scores and their changes over time pre- and post-operation.
A Word from ResRef about Pituitary Outcome Score (POS)
The Pituitary Outcome Score (POS) is a 25-item PROM developed for adults undergoing transsphenoidal surgery for pituitary adenoma. It demonstrates strong internal consistency and excellent test-retest reliability within its original single-center validation study. The POS enables domain-specific assessment of visual, endocrine, nasal symptoms, and quality of life, though independent external validation has not yet been reported. Overall, the POS remains a valuable, disease-specific measure for pituitary surgery outcomes.
References
Karvandi, E., Hanrahan, J.G., Khan, D.Z. et al.A patient-reported outcome measure for patients with pituitary adenoma undergoing transsphenoidal surgery. Pituitary 25, 673–683 (2022). linkAndela, C.D., Scharloo, M., Ramondt, S. et al.The development and validation of the Leiden Bother and Needs Questionnaire for patients with pituitary disease: the LBNQ-Pituitary. Pituitary 19, 293–302 (2016). link