Individual Regression Modeling of Spinal Mobility Measurements in Long-Term Ankylosing Spondylitis: In-Depth Analyses With Comparison to Norm Data.

OBJECTIVE: Normal age-related decline and temporary restrictions in mobility complicate the understanding of spinal mobility deterioration over time in patients with ankylosing spondylitis (AS). In this study, we aimed to determine whether spinal mobility deterioration occurred linearly in patients with AS. We also aimed to compare patterns of change with corresponding age-related normal values and analyze variations in temporary fluctuations in mobility measurements over time. METHODS: We included 111 men and 30 women (median age 20.9 years at symptom onset), who were followed for a median of 34 years since symptom onset. This inclusion resulted in 9,697 spinal mobility measurements for analysis. Individual linear regression models for development of lateral spinal flexion (LSF), the 10-cm Schober test (ST10), chest expansion (CE), and cervical rotation (CR) were analyzed and compared with normal age-related decline over time. RESULTS: The median values for the constants of all measurements were significantly lower than the norm data. However, LSF, ST10, and CE followed a yearly linear decline comparable to the norm data, whereas CR declined approximately twice as fast as expected from the norm data (beta median -0.62° [25th-75th percentile -1.16, -0.22] and -0.35° [25th-75th percentile -0.35, -0.35], respectively). Temporary fluctuations in LSF and CE were significantly higher during the early phase of the disease, with decreasing residuals over time. CONCLUSION: Based on median constants of our data, mobility restrictions related to AS seem to mainly occur during the first years of disease, indicating a narrow window of opportunity for prevention.

Inflammatory Arthritis and the Effect of Physical Activity on Quality of Life and Self-Reported Function: A Systematic Review and Meta-Analysis.

OBJECTIVE: Although physical activity is an evidence-based intervention that reduces disease-related symptoms and comorbidity in rheumatoid arthritis (RA), the effect of physical activity on self-reported function and quality of life (QoL) has not yet been analyzed. The present study synthesizes the evidence for the effectiveness of physical activity on QoL and self-reported function in adults with RA, spondyloarthritis (SpA), and psoriatic arthritis (PsA). METHODS: The databases PubMed, Embase, CINAHL, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched to identify relevant randomized controlled trials (RCTs). Screening, risk of bias assessment (using the RoB 2.0 tool), and data extraction were independently performed by 2 or more of the authors. Meta-analyses were conducted with a random-effects model. RESULTS: Systematic review included 55 RCTs, and meta-analysis included 37 RCTs. Of the 55 studies included, 76%, 20%, and 4% were designed to investigate RA, SpA, and PsA, respectively. In the RA studies, effects of physical activity on QoL and function were found compared to the group of inactive controls; no effects were found compared to the group of active controls. In the SpA studies, the effects of physical activity on QoL were in favor of the control group. Effects of physical activity on function were found compared to the group of inactive controls and sustained in fatigue and pain when compared to the group of active controls. In the PsA studies, no effects on QoL were found, but effects on function were noted when compared to the group of inactive controls. The effect size was below 0.30 in the majority of the comparisons. CONCLUSION: Physical activity may improve QoL and self-reported function in individuals with RA, SpA, and PsA. However, larger trials are needed, especially in SpA and PsA.

Isotemporal Substitution of Time Between Sleep and Physical Activity: Associations With Cardiovascular Risk Factors in Early Rheumatoid Arthritis.

OBJECTIVE: We aimed to determine relationships between objectively measured nightly sleep, sedentary behavior (SB), light physical activity (LPA), and moderate to vigorous physical activity (MVPA) with risk factors for cardiovascular disease (CVD) in patients with early rheumatoid arthritis (RA). Furthermore, we aimed to estimate consequences for these risk factors of theoretical displacements of 30 minutes per day in one behavior with the same duration of time in another. METHODS: This cross-sectional study included 78 patients with early RA. Nightly sleep, SB, LPA, and MVPA were assessed by a combined heart rate and accelerometer monitor. Associations with risk factors for CVD were analyzed using linear regression models and consequences of reallocating time between the behaviors by isotemporal substitution modeling. RESULTS: Median (Q1-Q3) nightly sleep duration was 4.6 (3.6-5.8) hours. Adjusted for monitor wear time, age, and sex, 30-minutes-longer sleep duration was associated with favorable changes in the values ß (95% confidence interval [CI]) for waist circumference by -2.2 (-3.5, -0.9) cm, body mass index (BMI) by -0.9 (-1.4, -0.4) kg/m2 , body fat by -1.5 (-2.3, -0.8)%, fat-free mass by 1.6 (0.8, 2.3)%, sleeping heart rate by -0.8 (-1.5, -0.1) beats per minute, and systolic blood pressure by -2.5 (-4.0, -1.0) mm Hg. Thirty-minute decreases in SB, LPA, or MVPA replaced with increased sleep was associated with decreased android fat and lower systolic blood pressure levels. Replacement of SB or LPA with MVPA yielded lower BMIs. CONCLUSION: Shorter sleep during the night is common among patients with early RA and is associated with adverse risk factors for CVD.

Aerobic capacity is associated with disease activity and cardiovascular risk factors in early rheumatoid arthritis.

OBJECTIVES: The aim of this study was to investigate aerobic capacity and its associations with disease activity and risk factors for cardiovascular disease (CVD) in early rheumatoid arthritis (RA). METHODS: This cross-sectional study included 67 patients with early RA. Aerobic capacity was estimated with the Åstrand submaximal test adjusted according to the Nord-Tröndelag Health Study formula. The following were also assessed: subclinical atherosclerosis by carotid intima-media thickness and pulse wave analysis; body composition by dual X-ray absorptiometry; estimated CVD mortality risk by the Systematic Coronary Risk Evaluation; disease activity by the Disease Activity Score 28, C-reactive protein and erythrocyte sedimentation rate; blood lipids by total cholesterol, low-density lipoproteins, high-density lipoproteins, and triglycerides; and functional ability by the Stanford health assessment questionnaire. Univariate and multiple linear regression analyses were performed to explore the associations between variables. RESULTS: The mean (SD) aerobic capacity was 31.6 (8.7) ml O2 -1 kg min-1 . Disease activity and risk factors for CVD were more favourable for patients with aerobic capacity above the median value. Aerobic capacity was associated with ESR and several CVD risk factors, independent of age and sex. In a multiple regression model that was adjusted for age and sex, aerobic capacity was significantly associated with per cent body fat (ß = -0.502, 95% CI [-0.671, -0.333]) and triglycerides (ß = -2.365, 95% CI [-4.252, -0.479]). CONCLUSIONS: Disease activity and risk factors for CVD were in favour for patients with a higher aerobic capacity. Aerobic capacity was associated with disease activity and several risk factors for CVD, independent of age and sex. In RA, these findings may provide insights into the benefits of using aerobic capacity as a marker to prevent CVD.

Long-Term Spinal Mobility in Ankylosing Spondylitis: A Repeated Cross-Sectional Study.

OBJECTIVE: To evaluate the course of impaired spinal mobility in patients with long-standing well-defined ankylosing spondylitis (AS). METHODS: Data from 232 patients with AS (186 men, 46 women) and 3,849 clinical measurements performed between February 1980 and June 2016 were analyzed. Lateral spinal flexion (LSF), the 10-cm Schober test, chest expansion (CE), and cervical rotation measurements were stratified by disease duration at 10-year intervals and compared with published age- and height-adjusted spinal mobility reference intervals as well as with fixed reference values commonly used in clinical practice. RESULTS: After 10 years of AS, most patients exhibited at least 1 measurement, most commonly LSF, that was under the 2.5th percentile of the adjusted reference interval (53% of men, 65% of women). In all measurements except CE, there were significant linear increases in the proportion of patients during 40 years of disease duration who exhibited impaired mobility. Measured LSF values <2.5th percentile (mean 14.8 cm) after 10 years were associated with further spinal mobility impairments later in the disease course. Fixed reference values yielded higher proportions of patients with impaired mobility compared with adjusted reference intervals. CONCLUSION: Impaired spinal mobility in AS is common after a 10-year disease duration. LSF below the 2.5th percentile at 10 years appeared to be associated with a worse prognosis. Fixed reference values overestimated spinal mobility impairments in AS and should be avoided.

Aerobic capacity over 16 years in patients with rheumatoid arthritis: Relationship to disease activity and risk factors for cardiovascular disease.

The aim of this study was to analyse the change in aerobic capacity from disease onset of rheumatoid arthritis (RA) over 16.2 years, and its associations with disease activity and cardiovascular risk factors. Twenty-five patients (20 f/5 m), diagnosed with RA 1995-2002 were tested at disease onset and after mean 16.2 years. Parameters measured were: sub-maximal ergometer test for aerobic capacity, functional ability, self-efficacy, ESR, CRP and DAS28. At follow-up, cardiovascular risk factors were assessed as blood lipids, glucose concentrations, waist circumference, body mass index (BMI), body composition, pulse wave analysis and carotid intima-media thickness. Aerobic capacity [median (IQR)] was 32.3 (27.9-42.1) ml O2/kg x min at disease onset, and 33.2 (28.4-38.9) at follow-up (p>0.05). Baseline aerobic capacity was associated with follow-up values of: BMI (rs = -.401, p = .047), waist circumference (rs = -.498, p = .011), peripheral pulse pressure (rs = -.415, p = .039) self-efficacy (rs = .420, p = .037) and aerobic capacity (rs = .557, p = .004). In multiple regression models adjusted for baseline aerobic capacity, disease activity at baseline and over time predicted aerobic capacity at follow-up (AUC DAS28, 0-24 months; ß = -.14, p = .004). At follow-up, aerobic capacity was inversely associated with blood glucose levels (rs = -.508, p = .016), BMI (rs = -.434, p = .030), body fat% (rs = -.419, p = .037), aortic pulse pressure (rs = -.405, p = .044), resting heart rate (rs = -.424, p = .034) and self-efficacy (rs = .464, p = .020) at follow-up. We conclude that the aerobic capacity was maintained over 16 years. High baseline aerobic capacity associated with favourable measures of cardiovascular risk factors at follow-up. Higher disease activity in early stages of RA predicted lower aerobic capacity after 16.2 years.