Table 2.

Commonly used, well-validated generic PROMs for measuring common PROs

Fatigue	The 13-item Functional Assessment of Chronic Illness Therapy–Fatigue Scale (FACIT–Fatigue) was originally developed for cancer patients. Most validation studies were therefore performed in cancer patients [100–102], but it has been validated and used across many other conditions. Evidence on structural validity (i.e. whether the scale measures one or two constructs) seems inconsistent. Some evidence for content validity, internal consistency and test–retest reliability was found in Turkish people with diabetes [103]. More information and available language versions can be found on the FACIT website. The PROMIS Fatigue item bank, short forms and CAT have been validated in several general and clinical populations, including people with kidney disease, and appear to be unidimensional [60, 104–107]. Evidence for construct validity, test–retest reliability and responsiveness of the PROMIS Fatigue CAT was found in Dutch people with diabetes (F. Rutters, unpublished results). The PROMIS Fatigue short forms are part of the commonly used PROMIS-29, PROMIS-43, and PROMIS-57 [108], which have been validated across general and clinical populations [108–114]. These measures have been used (but not validated) in people with diabetes in clinical practice and research [65, 115–117]. The FACIT–Fatigue has been adopted by the PROMIS initiative and is now also called the PROMIS SF v1.0 Fatigue 13a. Available language versions of PROMIS can be found on the HealthMeasures website (www.healthmeasures.net/explore-measurement-systems/promis/intro-to-promis/available-translations).
Pain	A single 11-point (i.e. 0–10) numerical rating scale (NRS) for measuring pain intensity was recommended by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) initiative as a core outcome measure in clinical trials of chronic pain treatments [118]. The NRS has been used (but not validated) in diabetes studies (e.g. Higgins et al [119]). The PROMIS Numeric Rating Scale v1.0–Pain Intensity 1a, for example, is an NRS that can be used as a standalone measure or as part of the commonly used PROMIS Global Health [69], PROMIS-29, PROMIS-43 and PROMIS-57 [108]. The PROMIS Global Health, PROMIS-29 and PROMIS-57 have been used (but not validated) in people with diabetes in clinical practice and research [65, 115–117, 120, 121]. The SF-36 is perhaps the most commonly used generic PROM in the world. It was included in more than 300 systematic reviews of measurement properties of PROMs, included in the COSMIN database [50]. The SF-36 subscale Bodily Pain asks about pain severity and the interference of pain with daily activities. Evidence for internal consistency, construct validity and responsiveness of the SF-36 has been found in people with diabetes (e.g. Huang et al [51], Ahroni and Boyko [52], and Martin et al [122]). Available language versions of the SF-36 can be found in the Patient-Reported Outcome and Quality of Life Instruments Database (PROQOLID) (https://www.qolid.org/instruments/sf_36_sup_r_sup_health_survey_and_sf_36v2_sup_tm_sup_health_survey_sf_36_sup_r_sup_sf_36v2_sup_tm_sup/).
Anxiety	The Generalized Anxiety Disorder-7 (GAD-7) is a brief screening tool developed to identify probable cases of generalised anxiety disorder and assess symptom severity [123]. It has been widely used and validated (e.g. Breedvelt et al [124] and Toussaint et al [125]). Findings regarding its structural validity are mixed, with most studies reporting it to be one scale (including a study in people with diabetes in India [126]), whereas others found two subscales [127]. Available language versions of the GAD-7 can be found on the website of Patient Health Questionnaire (PHQ) Screeners. The Hospital Anxiety and Depression Scale (HADS) was published in 1983 as a self-assessment scale for detecting states of depression and anxiety in a hospital setting [128]. The HADS is widely used and has been extensively validated in many different conditions [50] (some may include people with diabetes, but we found no validation study in only people with diabetes), although evidence on structural validity is inconsistent. The HADS consists of two subscales, measuring anxiety and depression, respectively, although others have suggested that it can be used as one unidimensional scale [129]. More information and available language versions of the HADS can be found on the ePROVIDE website (https://eprovide.mapi-trust.org/instruments/hospital-anxiety-and-depression-scale). The SF-36 subscale Mental health is widely used, and has been validated in people with diabetes (e.g. Huang et al [51], Ahroni and Boyko [52], and Martin et al [122]). The more recently developed PROMIS Anxiety item bank and derivative short forms and CAT were found to be unidimensional and have been validated in several general and clinical populations [130–133]. Evidence for sufficient construct validity, test–retest reliability and responsiveness of the PROMIS Anxiety CAT was found in Dutch people with diabetes (F. Rutters, unpublished results). The PROMIS Anxiety short forms are part of the commonly used PROMIS-29, PROMIS-43, and PROMIS-57 [108] (see above) [65, 115–117].
Depression	The HADS depression subscale is described above. van Dijk et al concluded in a systematic review that the generic Center for Epidemiologic Studies Depression scale (CESD) was best supported for measuring depressive symptoms in people with diabetes [21]. However, evidence on structural validity is inconsistent. Although the CESD is used as a unidimensional scale, most studies found three or four underlying concepts [134]. The CESD was revised to CESD-R in 2004. More information and available language translations can be found on the CESD website (https://cesd-r.com/). The Patient Health Questionnaire (PHQ-9) [135] has been used in more than 5000 studies listed on PubMed. It was included in more than 30 systematic reviews of measurement properties of PROMs [50]. van Dijk found evidence for construct validity, and criterion validity in people with diabetes, but evidence for structural validity was inconsistent [21]. Available language versions of the PHQ-9 can be found on the website of Patient Health Questionnaire (PHQ) Screeners (www.phqscreeners.com/select-screener). The SF-36 subscale Mental health (see above) is widely used, and has been validated in people with diabetes (e.g. Huang et al [51], Ahroni and Boyko [52], and Martin et al [122]). The more recently developed PROMIS Depression item bank and derivative short forms and CAT were found to be unidimensional and have been validated in several general and clinical populations [58, 132, 133, 136–138]. High internal consistency of the PROMIS Depression 8-item short form was found in people with diabetes [139]. Evidence for construct validity, test–retest reliability and responsiveness of the PROMIS Depression CAT was found in Dutch people with diabetes (F. Rutters, unpublished results). The PROMIS Depression short forms are part of the commonly used PROMIS-29, PROMIS-43 and PROMIS-57 [108] (see above), which have been used (but not validated) in people with diabetes in clinical practice and research [65, 115–117].
Sleep disturbances	The Pittsburgh Sleep Quality Index (PSQI) is the most frequently used measure of sleep quality. However, evidence on structural validity was found to be inconsistent [140]. It has been used in more than 5000 studies (PubMed) and was included in 28 systematic reviews of measurement properties of PROMs (https://database.cosmin.nl). More information and available language versions can be found on the ePROVIDE website (https://eprovide.mapi-trust.org/instruments/pittsburgh-sleep-quality-index). The PROMIS Sleep Disturbance and Sleep-Related Impairment item banks and derivative short forms and CAT were found to be unidimensional and have been validated in several general and clinical populations [141–144]. Evidence for construct validity, test–retest reliability and responsiveness of the PROMIS Sleep Disturbance CAT was found in Dutch people with diabetes (F. Rutters, unpublished results). Sufficient responsiveness of the short forms of both PROMIS measures was found in people with type 2 diabetes and sleep apnoea [145]. The PROMIS Sleep Disturbance short forms are part of the commonly used PROMIS-29, PROMIS-43 and PROMIS-57 [108] (see above), which have been used (but not validated) in people with diabetes in clinical practice and research, respectively [65, 115–117].
Physical function	Elsman et al concluded in a systematic review that the Diabetic Foot Ulcer Scale short form (DFS-SF) subscale Dependence/Daily Life (developed for people with diabetes and foot ulcers) and the IWADL could best be used to measure physical functioning in people with type 2 diabetes in research or clinical practice, although both scales have some limitations [24]. More information and available language versions of the DFS and DFS-SF can be found on the ePROVIDE website (https://eprovide.mapi-trust.org/instruments/diabetic-foot-ulcer-scale). The SF-36 subscale Physical Functioning (see above) is probably the most commonly used generic unidimensional physical function subscale and has been validated in people with diabetes (e.g. Huang et al [51], Ahroni and Boyko [52], and Martin et al [122]). The unidimensional PROMIS Physical Function item bank and derivative short forms and CAT are the most commonly used and most often translated measures of the PROMIS system and have been validated in several general and clinical populations, most often in people with musculoskeletal disorders [146–149]. Evidence for construct validity, test–retest reliability and responsiveness of the PROMIS Physical Function CAT was found in Dutch people with diabetes (F. Rutters, unpublished results). The PROMIS Physical Function short forms are part of the commonly used PROMIS-29, PROMIS-43 and PROMIS-57 [108] (see above), which have been used (but not validated) in people with diabetes in clinical practice and research, respectively [65, 115–117].
Sexual function	The most widely used measures of sexual function are the Female Sexual Function Index (FSFI) for women and the International Index of Erectile Function (IIEF) for men. However, conflicting and lack of evidence was found for some of their measurement properties [150, 151]. On the ePROVIDE website more information and available language versions can be found for the FSFI (https://eprovide.mapi-trust.org/instruments/female-sexual-function-index) and IIEF (https://eprovide.mapi-trust.org/instruments/international-index-of-erectile-function). The PROMIS Sexual Function and Satisfaction Profile measures for women and men were developed more recently and have been validated to at least some extent in cancer patients, but not yet in people with diabetes, and they have so far been used less often [152–154].
Cognitive function	The PROMIS Cognitive Function and Cognitive Function–Abilities item banks and derivative short forms and CAT have recently been developed as part of the PROMIS system and have been validated to some extent [155, 156].
Participation in social roles and activities	The SF-36 subscales Physical role functioning and Emotional role functioning are widely used, and have been validated in people with diabetes (e.g. Huang et al [51], Ahroni and Boyko [52], and Martin et al [122]). The WHODAS 2.0 is a generic instrument covering several domains of function and participation. The subscale Participation measure joining in community activities. The WHODAS 2.0 is one of the most widely validated measures of participation [157] and has been used in several large population studies (e.g. Alonso et al [54] and Thorpe et al [55]). It has not been validated in people with diabetes. More information on the WHODAS 2.0 and available language versions can be found on the WHO website (www.who.int/standards/classifications/international-classification-of-functioning-disability-and-health/who-disability-assessment-schedule). The PROMIS Ability to Participate in Social Roles and Activities and PROMIS Satisfaction with Social Roles and Activities item banks and derivative short forms and CAT have been validated in large general population samples and we found them to be unidimensional [158, 159]. Evidence for construct validity, test–retest reliability and responsiveness of the PROMIS Ability to Participate in Social Roles and Activities CAT was found in Dutch people with diabetes (F. Rutters, unpublished results). The PROMIS Ability to Participate in Social Roles and Activities short forms are part of the commonly used PROMIS-29, PROMIS-43 and PROMIS-57 [108] (see above), which have been used (but not validated) in people with diabetes in clinical practice and research, respectively [65, 115–117].
Perceived overall Health	The first item of the SF-36 (see above) refers to perceived overall health. This item was adopted by PROMIS (PROMIS Global01) as part of the PROMIS Global Health [69]. The PROMIS Global Health has been used (but not validated) in people with diabetes [115, 120, 121].