The confounder matrix: A tool to assess confounding bias in systematic reviews of observational studies of etiology.

Systematic reviews and meta-analyses are essential for drawing conclusions regarding etiologic associations between exposures or interventions and health outcomes. Observational studies comprise a substantive source of the evidence base. One major threat to their validity is residual confounding, which may occur when component studies adjust for different sets of confounders, fail to control for important confounders, or have classification errors resulting in only partial control of measured confounders. We present the confounder matrix-an approach for defining and summarizing adequate confounding control in systematic reviews of observational studies and incorporating this assessment into meta-analyses. First, an expert group reaches consensus regarding the core confounders that should be controlled and the best available method for their measurement. Second, a matrix graphically depicts how each component study accounted for each confounder. Third, the assessment of control adequacy informs quantitative synthesis. We illustrate the approach with studies of the association between short interpregnancy intervals and preterm birth. Our findings suggest that uncontrolled confounding, notably by reproductive history and sociodemographics, resulted in exaggerated estimates. Moreover, no studies adequately controlled for all core confounders, so we suspect residual confounding is present, even among studies with better control. The confounder matrix serves as an extension of previously published methodological guidance for observational research synthesis, enabling transparent reporting of confounding control and directly informing meta-analysis so that conclusions are drawn from the best available evidence. Widespread application could raise awareness about gaps across a body of work and allow for more valid inference with respect to confounder control.

Assessing the repercussions of COVID-19 pandemic on symptoms, disease management, and emotional well-being in patients with inflammatory bowel disease: a multi-site survey study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) pandemic has created numerous challenges in provision of safe and effective care for patients with Inflammatory Bowel Disease (IBD). In this study, we surveyed patients with IBD to highlight the impact of the pandemic on their IBD symptoms, management, and well-being. METHODS: A multi-site survey was administered to patients with IBD. We evaluated patient's symptoms, medications changes, seeking medical attention, eating behaviors, sleep patterns, stress, self-reported anxiety and depression. The survey also measured emotional impact of the pandemic using the validated Pandemic Emotional Impact Scale (PEIS) and resilience using the Brief Resilience Scale (BRS). Logistic, ordinal, and linear regression models were utilized to perform sensitivity analyses. RESULTS: The response rate to the survey was 61%. Of 391 surveyed patients, 21.1% reported worsened gastrointestinal symptoms, 17.5% reported changing biologic medication infusion schedule, 18.7% reported changing medication regimen, 43.6% attended at least one telemedicine visit with their gastroenterologist, 16.5% reported a less healthy diet, 40.5% reported worsening sleep, 63.7% reported more stress, and 65.3% reported feeling more vulnerable than before the pandemic. Women and participants with self-reported anxiety and depression were more likely to have worse symptoms, psychological well-being and daily functioning. Increased PEIS scores and decreased BRS scores were associated with worse outcomes. CONCLUSIONS: COVID-19 pandemic has impacted symptoms, disease management and well-being for patient with IBD, more prominently in patients who suffer from anxiety and depression. Utilizing PEIS and BRS scores as screening tools could help better tailor outreach and follow-up to support these patients.

Biomarkers of kidney injury among children in a high-risk region for chronic kidney disease of uncertain etiology.

BACKGROUND: Mesoamerican Nephropathy (MeN), a form of chronic kidney disease of uncertain etiology, is a leading cause of death in Central America. The disease often presents in young adult male agricultural workers and progresses rapidly. Given the young age at presentation, we hypothesized that children in Central America experience subclinical kidney injury prior to working life. METHODS: We assessed specimens from a cross-sectional study of youth, aged 7-17 years, predominantly residing in a high-risk region of Nicaragua (n = 210). We evaluated urinary concentrations and risk factors for kidney injury biomarkers neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), interleukin-18 (IL-18), monocyte chemoattractant protein 1 (MCP-1), and chitinase-3-like protein 1 (YKL-40). We evaluated the association between biomarkers and contemporaneous eGFR and compared biomarker concentrations with reference values from healthy children in other countries. RESULTS: Median uNGAL, uIL-18, and uKIM-1 concentrations exceeded healthy reference values. A one-year increase in age was associated with 40% increase in odds of being in the highest quartile of uNGAL (OR 1.4; (95%CI 1.2, 1.5); p < 0.0001). Youth who reported ever experiencing dysuria had 2.5 times the odds of having uNGAL concentrations in the top quartile (OR 2.5; (95%CI 1.4, 4.6); p = 0.003). Girls had significantly higher concentrations of all biomarkers than boys. Nine percent of children demonstrated low eGFR (≤ 100 ml/min/1.73 m2), while 29% showed evidence of hyperfiltration (eGFR ≥ 160 ml/min/1.73 m2), both potentially indicative of renal dysfunction. CONCLUSIONS: Children residing in regions of Nicaragua at high risk for MeN may experience subclinical kidney injury prior to occupational exposures.