Exploring Multimorbidity in Patients With Spinal Pain

Health related quality of life

The EQ-5D-5L questionnaire is a standardized measure of health-related quality of life recommended for multimorbidity research. The EQ-5D-5L assesses health status across five dimensions, including mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension is rated on a five-point ordinal scale ranging from 1 (indicating no problems) to 5 (indicating extreme difficulties) The EQ-5D index score can be regarded as a continuous outcome and ranges from -0.624 to 1, with higher scores indicating better general health and quality of life.

Brief Pain Inventory

The Brief Pain Inventory (BPI) is considered the secondary outcome variable. The questionnaire assesses pain in two dimensions: pain intensity and pain interference with function, mood, sleep, and social life, and is a recommended core outcome measure in clinical trials of chronic pain. All items are scored from 0-10, with 0 indicating no pain or interference and 10 indicating worst imaginable pain/completely interference. Hence the sum 0-40 is averaged between the four items about pain intensity, and the sum 0-70 is averaged between the seven items about pain interference.

Multimorbidity Treatment Burden Questionnaire (MTBQ)

MTBQ is considered the exposure variable. It is a 10-item self-reported measure designed to assess the burden experienced by individuals with multiple health conditions. The ten items cover various aspects of treatment burden, such as managing own health, including self-monitoring and lifestyle changes, dealing with medication-related challenges (e.g., adherence and obtaining prescriptions), coordinating healthcare appointments, and managing dependency on others. Each item is scored on a scale ranging from 0 to 100. A higher total score on the questionnaire indicates a higher burden.

Selected items from work ability index

In this project, five items from the Work Ability Index will be considered as covariates. These include items 1, 2, 4, 5, and 6. Item 1 asks patients to rate their current work ability compared to their lifetime best (Likert scale ranging from 0-10). Item 2 asks patients to rate their work ability in relation to the physical and mental demands of the job (Likert scale ranging from very poor to very good). Item 4 asks patients to estimate their work impairment due to their health (ranging from "in my opinion, I am entirely unable to work" to "There is no hindrance/ I have no diseases"). Item 5 asks patients to indicate the number of sick days in the past 12 months (Ranging from "None at all" to "100-365 days"), while item 6 asks patients to give their own assessment of their work ability in 2 years (Ranging from "Unlikely" to "Certain").

Insomnia Severity Index

To assess the patient's sleep quality, the Insomnia Severity Index (ISI) will be utilized. ISI includes seven questions that measure the severity of insomnia experienced over the past two weeks. Respondents assess the severity of difficulties in falling asleep, staying asleep, waking up too early, satisfaction with current sleep, as well as the degree of concern or anxiety caused by sleep problems. Additionally, the impact of sleep difficulties on daytime functioning and whether others notice any impairment related to the sleep issue are also addressed. A 5-point Likert scale (0-4) is used to rate the severity of each area based on the individual's experience. The total score ranges from 0 to 28, where a higher score indicates a greater severity of insomnia. ISI is considered a covariate.

EQ-5D-5L-VAS

EQ-5D-5L-VAS is a 100mm visual analogue scale (VAS) used to assess self-rated health. On this scale, 0 represents the worst imaginable health, while 100 represents the best imaginable health. EQ-5D-5L-VAS is considered a covariate.