Melatonin for Patients With Chronic Low Back Pain

Change in low back pain intensity (average pain intensity past 7 days), measured on a 0-10 Numeric Rating Scale (NRS) where 0 means no pain and 10 means worst pain imaginable, from baseline to 6 weeks

Back pain-related disability is measured using the Roland Morris Disability Questionnaire (RMDQ). The RMDQ outcome ranges from 0-24, where a higher score means more disability.

Using Global perceived effect (GPE) questionnaire (7-point scale), where a score of 1 means highly satisfied/ great recovery and a score of 7 means highly dissatisfied / poor recovery.

Physical and mental health measured using the PROMIS Global Health questionnaire.

A 10 items questionnaire, items are scored from 1-5 where a score of 5 is the best outcome and a score of 1 is the worst outcome.

Measured using the EQ-5D-5L (questionnaire).

The EQ-5D-5L consists of the EQ-5D descriptive system and the EQ visual analogue scale (EQ VAS). The descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems and extreme problems. The patient is asked to indicate his/her health state by ticking the box next to the most appropriate statement in each of the five dimensions. This decision results in a 1-digit number that expresses the level selected for that dimension. The digits for the five dimensions can be combined into a 5-digit number that describes the patient's health state. The EQ VAS (0-100) records the patient's self-rated health on a vertical visual analogue scale where the endpoints are labelled 'The best health you can imagine' and 'The worst health you can imagine'.

Measured using the Insomnia Severity Index (ISI) (questionnaire). The questionnaire consists of 7 questions, all scored with a score ranging from 0-3. The total score ranges from 0 (no sleeping problems) to 28 (severe sleeping problems)

Using a questionnaire

Measured using the Beck Depression Inventory (BDI) (questionnaire). A 21-item questionnaire, every item is scored from 0-3. This leads to a total score from 0 (best outcome) to 63 (worst outcome)

Measured using the Pain Anxiety Symptoms Scale (PASS) (questionnaire). A 40-item questionnaire (ranging from 0-200), where a high score means high pain related anxiety.

Measured using PainDETECT (questionnaire). A 9-item questionnaire, with 7 weighted descriptor items (from never to very strongly) and 2 items related to spatial and temporal pain characteristics.

A total score of 19 or more is indicative of likely neuropathic pain.

iMTA Productivity Cost Questionnaire is used. The questionnaire consists of 18 questions in total. To calculate the costs of production losses, volumes are multiplied by unit costs.

Direct costs of medical care measured using iMCQ Medical Consumption Questionnaire.

The questionnaire consists of 29 items. Questions are answered with yes/no, or participants are asked to fill in a number, for example "How many appointments with the physiotherapist did you have in the past 3 months?". The costs of medical consumption are calculated by multiplying measured volumes of care by the cost price per unit of care.

Using questionnaire according to the Common Terminology Criteria for Adverse Events (CTCAE)

A GENEActiv activity tracker is worn for a period of 7 days during the 6-week treatment period by a subgroup of 60 participants. This device can measure activity and sleep. This measure is use as an explorative objective and only descriptive statistics of the data will be given. GENEActiv software is used to analyse the data.

A GENEActiv activity tracker is worn for a period of 7 days during the 6-week treatment period by a subgroup of 60 participants. This device can measure activity and sleep. A sleep report is created using the GENEActiv software. This measure is used as an explorative measure, only descriptive statistics are done.