Table 1 Description of outcome scales used in studies in this review

Brief pain inventory (BPI)

Measures both the intensity of pain (sensory dimension) and interference of pain in the patient’s life (reactive dimension); it also queries the patient about pain relief, pain quality, and patient perception of the cause of pain

Scores range from 0 (no pain) to 10 (pain as bad as you can imagine)

A higher score indicates greater pain

Pain interference score (PIS)

Average score of four items on the BPI devoted to severity of pain

Scores range from 0 (does not interfere) to 10 (completely interferes)

A higher score indicates greater interference of pain

Pain severity score (PSS)

Calculated on the basis of the average interference of pain (assessed on the BPI) with the following seven activities: general activities, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life

Scores range from 0 (no pain) to 10 (pain as bad as you can imagine)

A higher score indicates greater pain

CarerQoL

Measure of care-related QoL in informal caregivers; comprising two parts: a description of the care situation on seven burden dimensions (CarerQoL-7D) and a valuation component in terms of general QoL using a Visual Analog Scale (CarerQol-VAS)

Assesses the overall well-being of the caregiver on a 0–10 scale, ranging from “completely unhappy” (0) to “completely happy” (10)

A higher score indicates greater happiness

Fatigue severity scale (FSS)

Self-reported nine-item questionnaire concerning the respondent’s fatigue; for example, how fatigue affects motivation, exercise, physical functioning, carrying out duties, interfering with work, family or social life

Participants grade each question on a Likert scale from 1 to 7, where 1 indicates strong disagreement and 7 indicates strong agreement

A higher score indicates more severe fatigue. Scores above 4 indicate significant fatigue and scores above 5 indicate severe fatigue

Hospital anxiety and depression scale (HADS)

14-item self-rated scale. Seven of the items relate to anxiety and seven relate to depression. Each item is rated from 0 to 3, where 0 = not at all to 3 = most severe

Depression and anxiety scores can each range from 0 to 21

Higher scores indicate greater anxiety or depression

Nottingham health profile (NHP)

Assesses subjective health status

Ranges from 0 (good) to 100 (poor)

Higher scores indicate poorer health status

Pittsburgh sleep quality index (PSQI)

19 self-rated questions and five questions rated by the partner. The latter five questions are used for clinical information only and are not tabulated in the scoring of the PSQI. The 19 self-rated questions assess a wide variety of factors relating to sleep quality, including estimates of sleep duration and latency, and the frequency and severity of specific sleep-related problems

Global PSQI score is calculated from the responses given using a predefined algorithm, and ranges from 0 to 21

A higher score indicates worse sleep quality

Rotterdam handicap scale (RHS)

Used to measure a patient’s functional ability and level of handicap, and can be used to monitor a patient’s status over time as well as to evaluate the effectiveness of interventions

Scores per item range from 1 (‘unable to fulfill the task or activity’) to 4 (‘complete fulfillment of the task or activity’). The total score is derived by adding individual component scores and ranges from 9 (‘unable to fulfill any task/activity’) to 36 (‘able to fulfill all applicable tasks or activities’)

A higher score indicates better functional ability

Short-form-36 (SF-36)

Multidimensional HRQoL instrument comprising four physical health scales (physical functioning, role limitations due to physical problems, bodily pain, and general health perceptions) and four mental health scales (vitality, social functioning, role limitations due to emotional problems, and mental health). These eight scales can be aggregated into two summary measures: the physical (PCS) and mental (MCS) component summary scores

Each scale is directly transformed into a 0–100 scale on the assumption that each question carries equal weight

A lower score indicates greater disability (i.e., a score of zero is equivalent to maximum disability and a score of 100 is equivalent to no disability)