2.3. Study Variables
Arthritis, daytime dysfunction, Pain, pain
ARTHRITIS, PAD
Clinical variables included age, sex, body mass index (BMI), and blood pressure. Pain was the primary efficacy variable and was measured using a 1–10 cm VAS scale (0 = no pain, 10 = worst imaginable pain), with scores < 4 categorized as mild pain, scores between 4 and 6 as moderate pain, and > 6 as severe pain. The intensity of pain was evaluated at visits 1 and 2 before muscle strength testing and at weekly intervals as self-reported by participants. The VAS scores were assessed each morning upon waking, with reference to the pain intensity encountered on the preceding day. Every day, the participants’ VAS scores were documented in individualized notebooks.Health-related QoL was evaluated according to the impact of the three subscales of pain (5 items), stiffness (2 items), and physical function (17 items) of the Western Ontario McMaster Universities Arthritis Index (WOMAC). Subjects were asked to answer each question with regard to pain, stiffness, or difficulty experienced in the previous 48 h. The test questions were scored on a scale of 0–4 (0 = none, 1 = slight, 2 = moderate, 3 = severe, 4 = extreme). Higher scores on the WOMAC indicate worse pain, stiffness, and functional limitations. A Spanish-validated version of the WOMAC index was administered [The Timed Up and Go test (TUG) was used to assess balance and mobility. Briefly, participants were seated correctly in a chair without using the armrests. They were instructed to stand up from the chair, walk a distance of 3 m, turn back to the chair, and then sit down. The time taken for this task, measured with a stopwatch, represented the individual’s TUG score. Two trials were performed with an interval of 30 s, and the average time was taken as the final score. A TUG score of 13.5 s or higher indicated a higher risk of falling, while a score below 13.5 s suggested better functional performance [Isokinetic and isometric dynamometry were used for the measurement of the muscle function of the knee. The Biodex System 3 (Biodex Medical Systems, Shirley, NY, USA) isokinetic dynamometer was used for isokinetic dynamometry tests. Exercises were performed on a cycle ergometer (W45, 70–75 rpm) with the alignment of the dynamometer and knee movement axes, and the resistance pad was fixed on the distal tibia (two-thirds). A warming-up period of 5 min was required. The initial value was taken as the active maximal knee extension (0–90° motion range). Then, five repetitions of maximal flexion and extension of the knee at 60° and 180°·sSleep quality was evaluated by actigraphy (ActiGraph wGT3X-BT accelerometer, ActiGraph, Pensacola, FL, USA), and the following variables were recorded: sleep latency, sleep efficiency, total time in bed, total sleep time, wakefulness after sleep onset, number of awakenings, and the average number in minutes of awakenings. The Pittsburgh Sleep Quality Index (PSQI) was also administered. It is a self-rated questionnaire that assesses sleep quality over an interval of 1 month. The overall score ranges between 0 and 21 and is the sum of seven components (sleep latency, subjective sleep quality, duration of sleep and sleep disturbances, habitual sleep efficiency, need for medication to sleep, and daytime dysfunction). Lower scores indicate better sleep quality. A Spanish-validated version of the PSQI was used [Capillary puncture in dried blood sample spots was the technique used for measurement of EPA and DHA bioavailability, with results expressed as % of fatty acids. We also calculated the EPA + DHA omega-3 index. A triaxial accelerometer was used to assess the physical activity level, with results expressed as metabolic equivalents (METs). A whole-body bioimpedance analyzer (Tanita BC-420MA, Tanita Corp., Tokyo, Japan) was used to determine corporal composition (body mass index (BMI), percentage of fat mass). Safety data included blood pressure recording and laboratory analyses. Standard hematological (hemogram) and biochemical parameters (renal and liver function tests) were measured.