We need to do better: A systematic review and meta-analysis of diagnostic test accuracy of restless legs syndrome screening instruments

This systematic review and meta-analysis evaluated the diagnostic accuracy of screening instruments for restless legs syndrome (RLS) and reports sensitivity, specificity, positive (PPV) and negative predictive values (NPV). Searches for primary studies were conducted in electronic databases. Of the 1541 citations identified, 52 were included in the meta-analysis. The methodological quality of each study was evaluated using QUADAS-2. Only 14 studies assessed the reference standard in all participants or in all screen-positives and a selection of screen-negatives. Bivariate meta-analysis of these 14 studies estimated median sensitivity to be 0.88 (0.72-0.96) and specificity 0.90 (0.84-0.93); based on a population prevalence of 5%, the calculated PPV was 0.31 (0.27-0.34). For all 52 studies, with either full or partial verification of RLS status, we constructed best-case scenario sensitivities and specificities at pre-defined levels of prevalence: across all samples, when prevalence is 5%, the median best-case scenario PPV is 0.48 with significant between-study heterogeneity. No RLS screening instruments can currently be recommended for use without an expert clinical interview in epidemiological studies. For conditions with statistically low prevalence such as RLS, the specificity, not the sensitivity, of a screening instrument determines true prevalence. Therefore, future instruments should maximize specificity. We provide guidelines on RLS ascertainment in epidemiological studies that requires a two-step process with clinical interview following a screening test, and given the poor reporting quality of many RLS epidemiological studies, we include an RLS reporting checklist.

Are serum vitamin D, calcium and phosphorous associated with restless leg syndrome? A systematic review and meta-analysis

BACKGROUND

It is hypothesized that vitamin D deficiency, and calcium/phosphate imbalance could be involved in the pathophysiology of restless leg syndrome (RLS). This systematic review and meta-analysis of observational studies were carried out to reach a firm conclusion regarding the possible association between vitamin D, calcium and phosphorous levels with RLS in end-stage renal disease (ESRD) patients, other comorbidities and healthy population.

METHODS

PubMed, Scopus, ISI Web of Science, and Cochrane's library were systematically searched up to June 2020. Quality assessment of the included observational studies was performed using Newcastle-Ottawa Quality Assessment Scale. Statistical analyses were done using STATA 11.2. A P-value <0.05 were considered statistically significant.

RESULTS

A total of 36 studies involving 9590 participants were included in this systematic review and meta-analysis. We found that serum vitamin D level is significantly lower (WMD -3.39 ng/mL; 95% CI, -5.96 to -0.81; P = 0.010; I² = 86.2%) and phosphorous (SMD 0.19; 95% CI, 0.04-0.34; P = 0.011; I² = 83.6%) is significantly higher in RLS individuals compared to the non-RLS individuals. However, the mean difference of serum calcium was not significant in comparison between RLS and control groups (SMD -0.01; 95% CI, -0.19 to 0.18; P = 0.957; I² = 89.2%).

CONCLUSION

Results revealed a significant association between serum vitamin D and phosphorous with RLS. However, further prospective cohort studies and clinical trials are needed for better understanding of the relationship between these variables.