Comparisons of sleep apnoea rate and outcomes among patients with resistant and non-resistant hypertension.

BACKGROUND AND OBJECTIVE: We directly compared sleep apnoea (SA) rates and risk of cardiovascular and mortality outcomes among SA patients with resistant hypertension (RH) and non-RH within a large diverse hypertension population. METHODS: A retrospective cohort study between 1 January 2006 and 31 December 2010 among hypertensive adults (age ≥ 18 years) was performed within an integrated health system. Rates of SA in RH and non-RH were determined. Multivariable logistic regression analyses were used to calculate OR for SA. Cox proportional hazard modelling was used to estimate hazard ratios (HRs) for cardiovascular and mortality outcomes between SA in RH versus SA in non-RH adjusting for age, gender, race, BMI, chronic kidney disease and other comorbidities. RESULTS: SA was identified in 33 682 (7.2%) from 470 386 hypertensive individuals. SA in RH accounted for 5806 (9.6%) compared to SA in non-RH 27 876 individuals (6.8%). Multivariable OR (95% CI) for SA was 1.16 (1.12, 1.19), 3.57 (3.47, 3.66) and 2.20 (2.15, 2.25) for RH versus non-RH, BMI ≥ 30, and males, respectively. Compared to SA in non-RH individuals, SA in RH had a multivariable adjusted HR (95% CI) of 1.24 (1.13, 1.36), 1.43 (1.28, 1.61), 0.98 (0.85, 1.12) and 1.04 (0.95, 1.14) for ischaemic heart event (IHE), congestive heart failure (CHF), stroke and mortality, respectively. CONCLUSION: We observed a modest increase in likelihood for SA among RH compared to non-RH patients. Risks for IHE and CHF were higher for SA in RH compared to SA in non-RH patients; however, there were no differences in risk for stroke and mortality.

25-hydroxyvitamin D levels and hypertension rates.

Vitamin D deficiency has been linked to cardiovascular disease and risk factors including hypertension. The authors sought to determine prevalence rates of hypertension in adults tested for 25-hydroxyvitamin D categorized by their levels and evaluate odds ratios for hypertension at lower 25-hydroxyvitamin D levels compared with optimal levels. A cross-sectional study was conducted January 1, 2004, through December 31, 2006, of patients aged 18 years and older within a large ethnically diverse population. Diagnosis of hypertension was determined by International Statistical Classification of Diseases and Related Health Problems codes. Patients were categorized into quartiles according to 25-hydroxyvitamin D levels: ideal (≥40 ng/mL), adequate (30-39 ng/mL), deficient (15-29 ng/mL), and severely deficient (<15 ng/mL). Prevalence rates of hypertension and odds ratios were calculated for each 25-hydroxyvitamin D quartile, adjusting for age, sex, race, and renal insufficiency. A total of 2722 individuals met the inclusion criteria for the study. The overall prevalence of hypertension in the study population was 24%. Hypertension rates were 52%, 41%, 27%, and 20% in 25-hydroxyvitamin D quartiles <15 ng/mL, 15 to 29 ng/mL, 30 to 39 ng/mL, and ≥40 ng/mL, respectively (P<.001). Odds ratios (95% confidence intervals) for hypertension adjusting for age, sex, race, and renal insufficiency were 2.7 (1.4-5.2), 2.0 (1.5-2.6), and 1.3 (1.2-1.6) for 25-hydroxyvitamin D levels <15 ng/mL, 15 to 29 ng/mL, and 30 to 39 ng/mL, respectively, compared with the ≥40 ng/mL group. This study demonstrates increased rates of hypertension in individuals who tested for lower levels of 25-hydroxyvitamin D starting at levels <40 ng/mL. This retrospective analysis raises the question of whether supplementing to optimal vitamin D levels can prevent or improve hypertension.

Vitamin D supplementation and recombinant human erythropoietin utilization in vitamin D-deficient hemodialysis patients.

INTRODUCTION: We sought to examine the impact of ergocalciferol (ERGO) on recombinant human erythropoietin (EPO) use in a cohort of 25-OH vitamin D (25-D)-deficient hemodialysis (HD) patients. METHODS: Baseline 25-D levels were obtained for all patients who received HD >6 months in our unit. Patients with levels between 10 and 30 ng/mL received ERGO 50,000 IU x 4 doses and patients with levels <10 ng/mL received 50,000 IU x 6 doses over a 4-month period. Monthly dose of EPO was recorded at baseline and after ERGO supplementation. RESULTS: Baseline 25-D levels were <30 ng/mL in 89% of tested patients. Eighty-one patients were included in this study. Mean baseline 25-D level was 15.3 ± 7.1 ng/mL and increased to 28.5 ± 8.6 ng/mL after ERGO (p<0.0001), and median baseline EPO dose was 21,933 U/month (interquartile range [IQR] 13,867-35,967) and decreased to 18,400 U/month (IQR 11,050-33,000) after ERGO (p=0.17). Forty-six patients (57%) required less EPO after ERGO compared with baseline: 15,450 U/month (IQR 10,056-23,575) vs. 26,242 U/month (IQR 15,717-40,167), respectively (p<0.0001). Thirty-five patients (43%) required a higher dose of EPO after ERGO, 26,350 U/month (IQR 15,875-46,075) vs. 17,667 U/month (IQR 12,021-23,392), respectively (p=0.016). Mean age, sex, vintage, diabetes status, race and 25-D levels did not differ in these 2 groups of patients, either at baseline or after ERGO. Monthly hemoglobin, iron saturation, albumin, intact parathyroid hormone, calcium and phosphorus were unchanged after ERGO in these 2 groups. CONCLUSIONS: ERGO use in 25-D-deficient HD patients may lessen the need for EPO. We recommend more aggressive supplementation with ERGO in future studies to achieve levels >30 ng/mL.

Sleep apnea in early and advanced chronic kidney disease: Kaiser Permanente Southern California cohort.

BACKGROUND: Sleep apnea (SA) has been reported to be highly prevalent in the dialysis population. The reported rates of SA in dialysis are severalfold greater than the 2 to 4% estimated in the general population. This study sought to determine whether an association exists between SA and early stages of chronic kidney disease (CKD) where SA may represent an important comorbidity and potential risk factor in kidney disease. METHODS: Cross-sectional study of adults from an integrated health plan with documented serum creatinine levels in the period January 1, 2002, through December 31, 2004. SA diagnosis determined by International Classification of Diseases, ninth revision, coding for SA and Current Procedural Terminology coding for positive airway pressure devices. Kidney function was determined by the estimated glomerular filtration rate (eGFR). Logistic was regression used to estimate the relative risk for SA. RESULTS: The overall prevalence of SA was 2.5% in the study population that included subjects with normal renal function and those with CKD. The odds ratios (ORs) for SA by eGFRs of 75 to 89, 60 to 74, 45 to 59, 30 to 44, and 15 to 29 mL/min per 1.73 m(2), respectively, compared to normal kidney function, after adjustment for age, sex, and number of visits, were as follows: 1.22 (95% confidence interval [CI], 1.18 to 1.25); 1.32 (95% CI, 1.27 to 1.37); 1.42 (95% CI, 1.35 to 1.50); 1.37 (95% CI, 1.25 to 1.50); and 1.32 (95% CI, 1.13 to 1.55). The increased ORs for eGFRs > 45 mL/min per 1.73 m(2) were sustained even after controlling for diabetes, heart failure, and hypertension. CONCLUSION: This study demonstrated an increased risk of SA in patients with early CKD. Further evidence of a causal relationship should be sought in the hope that the detection and management of SA may improve the course of CKD.

Sleep apnea and hypertension: prevalence in chronic kidney disease.

The authors sought to evaluate the prevalence of hypertension (HTN) in patients with sleep apnea (SA) who had normal kidney function and in patients with SA and chronic kidney disease (CKD). It has not been determined whether there is an effect of interplay of SA and CKD on the prevalence of HTN. In this study, the diagnosis of CKD was established based on the glomerular filtration rate and the presence of proteinuria. SA and HTN were diagnosed based on International Classification of Diseases, Ninth Revision coding, Current Procedural Terminology coding, and medication use. Using the database of a large integrated health system, 434,388 patients aged 18 years and older with 2 or more years of continuous enrollment during January 2002 to December 2004 were analyzed. The HTN rate with SA alone was 51%, compared with 70.2% with SA and CKD. The overall prevalence of HTN was 28% in patients without CKD or SA. The prevalence ratio for HTN was 1.36 (95% confidence interval, 1.33-1.39) more prevalent in patients with SA and CKD compared with patients with SA without CKD. The high prevalence of HTN in patients with SA and CKD suggests the need for evaluation of SA in patients with concurrent HTN and CKD.