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2015
BACKGROUND AND OBJECTIVES
Common apolipoprotein L1 (APOL1) variants are associated with increased risk of progressive CKD; however, not all individuals with high-risk APOL1 variants experience CKD progression. Identification of factors contributing to heterogeneity has important scientific and clinical implications.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS
Using multivariable Cox models, we analyzed data from 693 participants in the African American Study of Kidney Disease and Hypertension to identify factors that modify the association between APOL1 genotypes and CKD progression (doubling of serum creatinine or incident ESRD).
RESULTS
Participant mean age was 54 years old, median GFR was 49 ml/min per 1.73 m(2), and 23% had the APOL1 high-risk genotype (two copies of the high-risk allele). Over a mean follow-up of 7.8 years, 288 (42%) participants experienced CKD progression. As previously reported, the high-risk genotype was associated with higher risk of CKD progression compared with the low-risk genotype (hazard ratio [HR], 1.88; 95% confidence interval [95% CI], 1.46 to 2.41). Although we found some suggestion that obesity (HR, 1.48; 95% CI, 1.05 to 2.08 and HR, 2.44; 95% CI, 1.66 to 3.57 for body mass index ≥ 30 versus <30 kg/m(2); P interaction =0.04) and increased urinary excretion of urea nitrogen (HR, 1.43; 95% CI, 0.98 to 2.09 versus HR, 2.33; 95% CI, 1.65 to 3.30 for urine urea nitrogen ≥ 8 versus <8 g/d; P interaction =0.04) were associated with lower APOL1-associated risk for CKD progression, these findings were not robust in sensitivity analyses with alternative cut points. No other sociodemographic (e.g., education and income), clinical (e.g., systolic BP and smoking), or laboratory (e.g., net endogenous acid production, urinary sodium and potassium excretions, 25-hydroxy vitamin D, intact parathyroid hormone, or fibroblast growth factor 23) variables modified the association between APOL1 and CKD progression (P interaction >0.05 for each).
CONCLUSIONS
Sociodemographic factors and common risk factors for CKD progression do not seem to alter APOL1-related CKD progression. Additional investigation is needed to identify nontraditional factors that may affect the association between APOL1 and progressive CKD.
View on PubMed2015
BACKGROUND
Cardiac injury is a known potential complication of influenza infection. Because U.S. veterans cared for at the U.S. Department of Veterans Affairs are older and have more cardiovascular disease (CVD) risk factors than the general U.S. population, veterans are at risk for cardiac complications of influenza infection. We investigated biomarkers of cardiac injury characteristics and associated cardiac events among veterans who received cardiac biomarker testing ≤30 days after laboratory-confirmed influenza virus infection.
METHODS
Laboratory-confirmed influenza cases among veterans cared for at U.S. Department of Veterans Affairs' facilities for October 2010-December 2012 were identified using electronic medical records (EMRs). Influenza confirmation was based on respiratory specimen viral culture or antigen or nucleic acid detection. Acute cardiac injury (ACI) was defined as an elevated cardiac biomarker (troponin I or creatinine kinase isoenzyme MB) >99 % of the upper reference limit occurring ≤30 days after influenza specimen collection. EMRs were reviewed for demographics, CVD history and risk factors, and ACI-associated cardiac events.
RESULTS
Among 38,197 patients with influenza testing results, 4,469 (12 %) had a positive result; 600 of those patients had cardiac biomarker testing performed ≤30 days after influenza testing, and 143 (24 %) had one or more elevated cardiac biomarkers. Among these 143, median age was 73 years (range 44-98 years), and 98 (69 %) were non-Hispanic white. All patients had one or more CVD risk factors, and 98 (69 %) had a history of CVD. Eighty-six percent of ACI-associated events occurred within 3 days of influenza specimen collection date. Seventy patients (49 %) had documented or probable acute myocardial infarction, 8 (6 %) acute congestive heart failure, 6 (4 %) myocarditis, and 4 (3 %) atrial fibrillation. Eleven (8 %) had non-cardiac explanations for elevated cardiac biomarkers, and 44 (31 %) had no documented explanation. Sixty-eight (48 %) patients had received influenza vaccination during the related influenza season.
CONCLUSION
Among veterans with laboratory-confirmed influenza infection and cardiac biomarker testing ≤30 days after influenza testing, approximately 25 % had evidence of ACI, the majority within 3 days. Approximately half were myocardial infarctions. Our findings emphasize the importance of considering ACI associated with influenza infection among patients at high risk, including this older population with prevalent CVD risk factors.
View on PubMed2015
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