Guideline-based strategies to prevent chronic kidney disease (CKD) progression and complications are available, yet their implementation in clinical practice is uncertain. We aimed to synthesise the available evidence on the concordance of CKD care with clinical guidelines to identify gaps and inform future CKD care.

Systematic review and meta-analysis.

We systematically searched MEDLINE (OVID), EMBASE (OVID) and CINAHL (EBSCOhost) (to 18 July 2025) for observational studies of adults with CKD reporting data on the quality of CKD care. We assessed data on quality indicators of CKD care across domains that related to patient monitoring (glomerular filtration rate and albuminuria), medications use (ACE inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), statins) and treatment targets (blood pressure (BP) and HbA1c). Pooled estimates (95% CI) of the percentage of patients who met the quality indicators for CKD care were estimated using random effects model.

59 studies across 24 countries, including a total of 3 003 641 patients with CKD, were included. Across studies, 81.3% (95% CI: 75% to 87.6%) of patients received eGFR monitoring, 47.4% (95% CI: 40.0% to 54.7%) had albuminuria testing, and 90% (95% CI: 84.3% to 95.9%) had BP measured. ACEIs/ARBs were prescribed among 56.7% (95% CI: 51.5% to 62%), and statins among 56.6% (95% CI: 48.9% to 64.3%) of patients. BP (systolic BP ≤140/90 mm Hg) and HbA1c (

Current evidence shows substantial variation in CKD care quality globally. Guideline-concordant care varied according to quality measures and across patient groups, with gaps in indicators like albuminuria testing. These findings underscore the need for effective quality improvement strategies to address gaps in CKD care, including increased albuminuria testing for risk stratification, together with systematic measures for monitoring care quality.

CRD42023391749.

SARS-CoV-2 infection provides protection against reinfection and severe COVID-19 disease; however, this protective effect may diminish over time. We assessed waning of natural immunity conferred by previous infection against severe disease and symptomatic reinfection in Brazil and Scotland.

We undertook a test-negative design study and nested case–control analysis to estimate waning of natural immunity against severe COVID-19 outcomes and symptomatic reinfection using national linked datasets. We used logistic regression to estimate ORs with 95% CIs. A stratified analysis assessed immunity during the Omicron dominant period in Brazil.

We included data from the adult populations of Brazil and Scotland from 1 June 2020 to 30 April 2022.

Severe COVID-19 was defined as hospitalisation or death. Reinfection was defined as reverse-transcriptase PCR or rapid antigen test confirmed at least 120 days after primary infection.

From Brazil, we included 30 881 873 tests and 1 301 665 severe COVID-19 outcomes, and from Scotland, we included 1 520 201 tests and 7988 severe COVID-19 outcomes. Against severe outcomes, sustained protection was observed for at least 12 months after primary SARS-CoV-2 infection with little evidence of waning: 12 months postprimary infection: Brazil OR 0.12 (95% CI 0.10 to 0.14), Scotland OR 0.03 (95% CI 0.02 to 0.04). For symptomatic reinfection, Brazilian data demonstrated evidence of waning in the 12 months following primary infection, although some residual protection remained beyond 12 months: 12 months postprimary infection: OR 0.42 (95% CI 0.40 to 0.43). The greatest reduction in risk of SARS-CoV-2 infection was in individuals with hybrid immunity (history of previous infection and vaccination), with sustained protection against severe outcomes at 12 months postprimary infection. During the Omicron dominant period in Brazil, odds of symptomatic reinfection were higher and increased more quickly over time when compared with the overall study period, although protection against severe outcomes was sustained at 12 months postprimary infection (whole study: OR 0.12 (95% CI 0.10 to 0.14); Omicron phase: OR 0.15 (95% CI 0.12 to 0.19)).

Cross-national analyses demonstrate sustained protection against severe COVID-19 disease for at least 12 months following natural SARS-CoV-2 infection, with vaccination further enhancing protection. Protection against symptomatic reinfection was lower with evidence of waning, but there remained a protective effect beyond 12 months from primary infection.

Minority ethnic groups disproportionately experienced adverse COVID-19 outcomes, partly a consequence of disproportionate exposure to socioeconomic disadvantage and high-risk occupations. We examined whether minority ethnic groups were also disproportionately vulnerable to the consequences of socioeconomic disadvantage and high-risk occupations in Scotland.

We investigated effect modification and interaction between area deprivation, education and occupational risk and ethnicity (assessed as both a binary white vs non-white variable and a multi-category variable) in relation to severe COVID-19 (hospitalisation or death). We used electronic health records linked to the 2011 census and Cox proportional hazards models, adjusting for age, sex and health board. We were principally concerned with additive interactions as a measure of vulnerability, estimated as the relative excess risk due to interaction (RERI).

Analyses considered 3 730 837 individuals aged ≥16 years (with narrower age ranges for analyses focused on education and occupation). Severe COVID-19 risk was typically higher for minority ethnic groups and disadvantaged socioeconomic groups, but additive interactions were not consistent. For example, non-white ethnicity and highest deprivation level experienced elevated risk ((HR=2.7, 95% CI: 2.4, 3.2) compared with the white least deprived group. Additive interaction was not present (RERI=–0.1, 95% CI: –0.4, 0.2), this risk being less than the sum of risks of white ethnicity/highest deprivation level (HR=2.4, 95% CI: 2.3, 2.5) and non-white ethnicity/lowest deprivation level (1.4, 95% CI: 1.2, 1.7). Similarly, non-white ethnicity/no degree education (HR=2.5, 95% CI: 2.2, 2.7; RERI=–0.1, 95% CI: –0.4, 0.2) and non-white ethnicity/high-risk occupation (RERI=0.3, 95% CI: –0.2, 0.8) did not experience greater than additive risk. No clear evidence of effect modification was identified when using the multicategory ethnicity variable or on the multiplicative scale either.

We found no definitive evidence that minority ethnic groups were more vulnerable to the effect of social disadvantage on the risk of severe COVID-19.