Cognition and renal function: findings from a Brazilian population / Cognição e função renal: achados de uma população brasileira

ABSTRACT Introduction: The prevalence of chronic kidney disease (CKD) is increasing, with a potential impact in the risk of acceleration of dementia. The potential association between glomerular filtration rate (eGFR) and cognitive performance was scarcely studied. The aim of this study was to evaluate cognitive performance levels across different degrees of kidney function. Methods: We analyzed 240 outpatients in a nephrology service, classified according to eGFR: Advanced (≤ 30ml/min/1.73m2), Moderate (30,1ml/min/1.73m2 to ≤ 60ml/min/1.73m2), and Mild CKD (> 60ml/min/1.73m2). Word list memory, Semantic fluency, Mental State Mini Exam and Trail Making Test (TMT) were applied to evaluate cognitive performance. In the TMT, lower scores are associated with better cognition. In linear regression, cognitive function was considered as dependent variables while groups based on eGFR were considered explanatory variables. The group with eGFR > 60ml/min was the reference and models were adjusted for confounding factors. Results: In our population (n = 240) 64 patients (26.7%) were classified as having advanced, 98(40,8%) moderate, and 78(32,5%) mild. There was no statistical difference among them in MMSE or in the verbal fluency test. However, comparing to mild, patients with advanced CKD presented significantly worse cognitive performance measured by TMTA [50,8s ± 31.1s versus 66,6s ± 35,7s (p = 0.016)] and TMTB [92,7s ± 46,2s versus 162,4s ± 35,7s (p < 0.001)]. Significantly lower TMTB scores (CI95%) 33,0s (4,5-61,6s) were observed in patients with mild compared to advanced CKD in the multivariate analysis adjusting for age, education, sex, diabetes, and alcohol use. Conclusion: Advanced CKD is independently associated with poorer cognitive performance measured by an executive performance test compared to mild CKD.

RESUMO Introdução: A elevação da prevalência de doença renal crônica (DRC) traz consigo um impacto potencial sobre o risco de aceleração da demência. A possível associação entre taxa de filtração glomerular (TFGe) e desempenho cognitivo foi pouco estudada. O objetivo do presente estudo foi avaliar os níveis de desempenho cognitivo em indivíduos com diferentes graus de função renal. Métodos: Foram analisados 240 pacientes ambulatoriais atendidos em um serviço de nefrologia classificados segundo a TFGe em grupos com DRC avançada (≤ 30ml/min/1,73m2), moderada (30,1ml/min/1,73m2 a ≤ 60ml/min/1,73m2) ou leve (> 60ml/min/1,73m2). Testes de memória por listas de palavras, fluência semântica, o mini exame do estado mental e o teste das trilhas (TT) foram aplicados para avaliar o desempenho cognitivo. No TT, escores mais baixos representam melhor cognição. Na regressão linear, função cognitiva foi considerada como variável dependente, enquanto os grupos baseados na TFGe foram considerados como variáveis explicativas. O grupo com TFGe > 60ml/min foi utilizado como referência e os modelos foram ajustados para fatores de confusão. Resultados: Em nossa população (n = 240), 64 pacientes (26,7%) foram diagnosticados com DRC avançada, 98 (40,8%) com DRC moderada e 78 (32,5%) com DRC leve. Não houve diferença estatística entre eles no MEEM ou no teste de fluência verbal. Contudo, em relação aos indivíduos com DRC leve, os pacientes com DRC avançada apresentaram desempenho cognitivo significativamente pior medido pelo TT A [50,8s ± 31,1s x 66,6s ± 35,7s (p = 0,016)] e TT B [92,7s ± 46,2s x 162,4s ± 35,7s (p < 0,001)]. Escores significativamente mais baixos no TT B (IC95%) 33,0s (4,5-61,6s) foram observados nos pacientes com DRC leve em comparação com o grupo com DRC avançada na análise multivariada ajustada para idade, escolaridade, sexo, diabetes e uso de álcool. Conclusão: DRC avançada esteve independentemente associada a pior desempenho cognitivo medido por um teste de desempenho executivo em comparação à DRC leve.

Cognition and renal function: findings from a Brazilian population.

INTRODUCTION: The prevalence of chronic kidney disease (CKD) is increasing, with a potential impact in the risk of acceleration of dementia. The potential association between glomerular filtration rate (eGFR) and cognitive performance was scarcely studied. The aim of this study was to evaluate cognitive performance levels across different degrees of kidney function. METHODS: We analyzed 240 outpatients in a nephrology service, classified according to eGFR: Advanced (≤ 30ml/min/1.73m2), Moderate (30,1ml/min/1.73m2 to ≤ 60ml/min/1.73m2), and Mild CKD (> 60ml/min/1.73m2). Word list memory, Semantic fluency, Mental State Mini Exam and Trail Making Test (TMT) were applied to evaluate cognitive performance. In the TMT, lower scores are associated with better cognition. In linear regression, cognitive function was considered as dependent variables while groups based on eGFR were considered explanatory variables. The group with eGFR > 60ml/min was the reference and models were adjusted for confounding factors. RESULTS: In our population (n = 240) 64 patients (26.7%) were classified as having advanced, 98(40,8%) moderate, and 78(32,5%) mild. There was no statistical difference among them in MMSE or in the verbal fluency test. However, comparing to mild, patients with advanced CKD presented significantly worse cognitive performance measured by TMTA [50,8s ± 31.1s versus 66,6s ± 35,7s (p = 0.016)] and TMTB [92,7s ± 46,2s versus 162,4s ± 35,7s (p < 0.001)]. Significantly lower TMTB scores (CI95%) 33,0s (4,5-61,6s) were observed in patients with mild compared to advanced CKD in the multivariate analysis adjusting for age, education, sex, diabetes, and alcohol use. CONCLUSION: Advanced CKD is independently associated with poorer cognitive performance measured by an executive performance test compared to mild CKD.

The effect of ivabradine therapy on heart failure patients with reduced ejection fraction: a systematic review and meta-analysis.

Background Ivabradine is currently indicated to lower heart rate in Heart Failure with Reduced Ejection Fraction (HFrEF) patients. However its effect apart from beta-blockers is not clear. Aim of the review To study the additional effect of ivabradine, apart from the effect of beta-blockers, on cardiovascular death, all-cause mortality, hospitalization due to HF and heart rate in HFrEF population. Method Electronic searches were conducted up to June 2016 to include randomized controlled trials where ivabradine was compared to a control group. Relative risks RRs and their 95% confidence intervals (CI 95%) were pooled and the random and fixed effect were used to summarize the results according to heterogeneity levels. Heterogeneity among studies was measured by the I-squared statistic Results Of 1790 studies, seven met the inclusion criteria for the systematic review and meta-analysis. The population consisted of 17,747 patients. Risk of bias was generally high for beta-blocker doses lower than recommended. Interventions lasted 1.5-22.9 months and pooled relative risks RR (95%) for all-cause mortality, cardiovascular death and hospitalization for HF were 0.98 (0.90-1.06); 0.99 (0.91-1.08); and 0.87 (0.68-1.12) respectively. Heart rate (CI 95%) decreased by 8.7 (6.37-11.03) beats per minute with ivabradine compared to the control group. Subgroup analysis by beta-blocker dose showed that for patients on recommended treatment (at least 50% of the beta-blocker target dose), heart rate (CI 95%) decreased by 4.70 (3.67-5.73), whereas for patients not on recommended treatment or with unreported dose, heart rate decreased by 8.60 (8.13-9.08). Conclusion Ivabradine significantly reduced heart rate and its additional effect on heart rate appears to be inversely correlated with the dose of beta-blocker. It showed no significant effect for all-cause mortality, cardiovascular death and hospitalization due to HF. Unreported beta-blocker doses and beta-blocker doses lower than recommended limited the conclusions.