Mark Unruh

Sleep-disordered breathing and mortality: A prospective cohort study

In a cohort of 6,441 volunteers followed over an average of 8.2 years, Naresh Punjabi and colleagues find sleep-disordered breathing to be independently associated with mortality and identify predictive characteristics.

In-center hemodialysis six times per week versus three times per week

BACKGROUND In this randomized clinical trial, we aimed to determine whether increasing the frequency of in-center hemodialysis would result in beneficial changes in left ventricular mass, self-reported physical health, and other intermediate outcomes among patients undergoing maintenance hemodialysis. METHODS Patients were randomly assigned to undergo hemodialysis six times per week (frequent hemodialysis, 125 patients) or three times per week (conventional hemodialysis, 120 patients) for 12 months. The two coprimary composite outcomes were death or change (from baseline to 12 months) in left ventricular mass, as assessed by cardiac magnetic resonance imaging, and death or change in the physical-health composite score of the RAND 36-item health survey. Secondary outcomes included cognitive performance; self-reported depression; laboratory markers of nutrition, mineral metabolism, and anemia; blood pressure; and rates of hospitalization and of interventions related to vascular access. RESULTS Patients in the frequent-hemodialysis group averaged 5.2 sessions per week; the weekly standard Kt/V(urea) (the product of the urea clearance and the duration of the dialysis session normalized to the volume of distribution of urea) was significantly higher in the frequent-hemodialysis group than in the conventional-hemodialysis group (3.54±0.56 vs. 2.49±0.27). Frequent hemodialysis was associated with significant benefits with respect to both coprimary composite outcomes (hazard ratio for death or increase in left ventricular mass, 0.61; 95% confidence interval [CI], 0.46 to 0.82; hazard ratio for death or a decrease in the physical-health composite score, 0.70; 95% CI, 0.53 to 0.92). Patients randomly assigned to frequent hemodialysis were more likely to undergo interventions related to vascular access than were patients assigned to conventional hemodialysis (hazard ratio, 1.71; 95% CI, 1.08 to 2.73). Frequent hemodialysis was associated with improved control of hypertension and hyperphosphatemia. There were no significant effects of frequent hemodialysis on cognitive performance, self-reported depression, serum albumin concentration, or use of erythropoiesis-stimulating agents. CONCLUSIONS Frequent hemodialysis, as compared with conventional hemodialysis, was associated with favorable results with respect to the composite outcomes of death or change in left ventricular mass and death or change in a physical-health composite score but prompted more frequent interventions related to vascular access. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; ClinicalTrials.gov number, NCT00264758.).

Rates and risk factors for nonadherence to the medical regimen after adult solid organ transplantation.

Background. Despite the impact of medical regimen nonadherence on health outcomes after organ transplantation, there is mixed and conflicting evidence regarding the prevalence and predictors of posttransplant nonadherence. Clinicians require precise information on nonadherence rates in order to evaluate patients’ risks for this problem. Methods. A total of 147 studies of kidney, heart, liver, pancreas/kidney-pancreas, or lung/heart-lung recipients published between 1981 and 2005 were included in a meta-analysis. Average nonadherence rates were calculated for 10 areas of the medical regimen. Correlations between nonadherence and patient psychosocial risk factors were examined. Results. Across all types of transplantation, average nonadherence rates ranged from 1 to 4 cases per 100 patients per year (PPY) for substance use (tobacco, alcohol, illicit drugs), to 19 to 25 cases per 100 PPY for nonadherence to immunosuppressants, diet, exercise, and other healthcare requirements. Rates varied significantly by transplant type in two areas: immunosuppressant nonadherence was highest in kidney recipients (36 cases per 100 PPY vs. 7 to 15 cases in other recipients). Failure to exercise was highest in heart recipients (34 cases per 100 PPY vs. 9 to 22 cases in other recipients). Demographics, social support, and perceived health showed little correlation with nonadherence. Pretransplant substance use predicted posttransplant use. Conclusions. The estimated nonadherence rates, overall and by transplant type, allow clinicians to gauge patient risk and target resources accordingly. Nonadherence rates in some areas—including immunosuppressant use—appear unacceptably high. Weak correlations of most patient psychosocial factors with nonadherence suggest that attention should focus on other classes of variables (e.g., provider-related and systems-level factors), which may be more influential.

The effects of frequent nocturnal home hemodialysis: the Frequent Hemodialysis Network Nocturnal Trial

Prior small studies have shown multiple benefits of frequent nocturnal hemodialysis compared to conventional three times per week treatments. To study this further, we randomized 87 patients to three times per week conventional hemodialysis or to nocturnal hemodialysis six times per week, all with single-use high-flux dialyzers. The 45 patients in the frequent nocturnal arm had a 1.82-fold higher mean weekly stdKt/V(urea), a 1.74-fold higher average number of treatments per week, and a 2.45-fold higher average weekly treatment time than the 42 patients in the conventional arm. We did not find a significant effect of nocturnal hemodialysis for either of the two coprimary outcomes (death or left ventricular mass (measured by MRI) with a hazard ratio of 0.68, or of death or RAND Physical Health Composite with a hazard ratio of 0.91). Possible explanations for the left ventricular mass result include limited sample size and patient characteristics. Secondary outcomes included cognitive performance, self-reported depression, laboratory markers of nutrition, mineral metabolism and anemia, blood pressure and rates of hospitalization, and vascular access interventions. Patients in the nocturnal arm had improved control of hyperphosphatemia and hypertension, but no significant benefit among the other main secondary outcomes. There was a trend for increased vascular access events in the nocturnal arm. Thus, we were unable to demonstrate a definitive benefit of more frequent nocturnal hemodialysis for either coprimary outcome.

Meta-Analysis of Risk for Relapse to Substance Use After Transplantation of the Liver or Other Solid Organs

For patients receiving liver or other organ transplants for diseases associated with substance use, risk for relapse posttransplantation is a prominent clinical concern. However, there is little consensus regarding either the prevalence or risk factors for relapse to alcohol or illicit drug use in these patients. Moreover, the evidence is inconsistent as to whether patients with pretransplantation substance use histories show poorer posttransplantation medical adherence. We conducted a meta‐analysis of studies published between 1983 and 2005 to estimate relapse rates, rates of nonadherence to the medical regimen, and the association of potential risk factors with these rates. The analysis included 54 studies (50 liver, 3 kidney, and 1 heart). Average alcohol relapse rates (examined only in liver studies) were 5.6 cases per 100 patients per year (PPY) for relapse to any alcohol use and 2.5 cases per 100 PPY for relapse with heavy alcohol use. Illicit drug relapse averaged 3.7 cases per 100 PPY, with a significantly lower rate in liver vs. other recipients (1.9 vs. 6.1 cases). Average rates in other areas (tobacco use, immunosuppressant and clinic appointment nonadherence) were 2 to 10 cases per 100 PPY. Risk factors could be examined only for relapse to any alcohol use. Demographics and most pretransplantation characteristics showed little correlation with relapse. Poorer social support, family alcohol history, and pretransplantation abstinence of ≤6 months showed small but significant associations with relapse (r = 0.17‐0.21). Future research should focus on improving the prediction of risk for substance use relapse, and on testing interventions to promote continued abstinence posttransplantation. Liver Transpl 14:159–172. 2008.

Subjective and Objective Sleep Quality and Aging in the Sleep Heart Health Study

OBJECTIVES: To examine the extent to which subjective and objective sleep quality are related to age independent of chronic health conditions.

Sleep Apnea in Patients on Conventional Thrice-Weekly Hemodialysis: Comparison with Matched Controls from the Sleep Heart Health Study

Sleep-disordered breathing (SDB) has been noted commonly in hemodialysis (HD) patients, but it is not known whether this is related directly to the treatment of kidney failure with HD or to the higher prevalence of obesity and older age. Forty-six HD patients were compared with 137 participants from the Sleep Heart Health Study (SHHS) who were matched for age, gender, body mass index (BMI), and race. Home unattended polysomnography was performed and scored using similar protocols. The study sample was 62.7 +/- 10.1 yr, was predominantly male (72%) and white (63%), and had an average BMI of 28 +/- 5.3 kg/m(2). The HD sample had a higher systolic BP (137 versus 121 mmHg; P < 0.01) and a higher prevalence of diabetes (33 versus 9%; P < 0.01) and cardiovascular disease (33 versus 13%; P < 0.01) compared with the SHHS sample. The HD group had significantly less sleep time (320 versus 379 min; P < 0.0001) but similar sleep efficiency. HD patients had a higher frequency of arousals per hour (25.1 versus 17.1; P < 0.0001) and apnea-hypopneas per hour (27.2 versus 15.2; P < 0.0001) and greater percentage of the total sleep time below an oxygen saturation of 90% (7.2 versus 1.8; P < 0.0001). HD patients were more likely to have severe SDB (>30 respiratory events per hour) compared with the SHHS sample (odds ratio 4.07; 95% confidence interval 1.83 to 9.07). There was a strong association of HD with severe SDB and nocturnal hypoxemia independent of age, BMI, and the higher prevalence of chronic disease. The potential mechanisms for the higher likelihood of SDB in the HD population must be identified to provide specific prevention and therapy.

Fatigue in Patients Receiving Maintenance Dialysis: A Review of Definitions, Measures, and Contributing Factors

Fatigue is a debilitating symptom or side effect experienced by many patients on long-term dialysis therapy. Fatigue has a considerable effect on patient health-related quality of life and is viewed as being more important than survival by some patients. Renal providers face many challenges when attempting to reduce fatigue in dialysis patients. The lack of a reliable, valid, and sensitive fatigue scale complicates the accurate identification of this symptom. Symptoms of daytime sleepiness and depression overlap with fatigue, making it difficult to target specific therapies. Moreover, many chronic health conditions common in the long-term dialysis population may lead to the development of fatigue and contribute to the day-to-day and diurnal variation in fatigue in patients. Key to improving the assessment and treatment of fatigue is improving our understanding of potential mediators, as well as potential therapies. Cytokines have emerged as an important mediator of fatigue and have been studied extensively in patients with cancer-related fatigue. In addition, although erythropoietin-stimulating agents have been shown to mitigate fatigue, the recent controversy regarding erythropoietin-stimulating agent dosing in patients with chronic kidney disease suggests that erythropoietin-stimulating agent therapy may not serve as the sole therapy to improve fatigue in this population. In conclusion, fatigue is an important and often underrecognized symptom in the dialysis population. Possible interventions for minimizing fatigue in patients on long-term dialysis therapy should aim at improving health care provider awareness, developing improved methods of measurement, understanding the pathogenesis better, and managing known contributing factors.

Meta-Analysis of Medical Regimen Adherence Outcomes in Pediatric Solid Organ Transplantation*

Background. Adherence to the medical regimen after pediatric organ transplantation is important for maximizing good clinical outcomes. However, the literature provides inconsistent evidence regarding prevalence and risk factors for nonadherence posttransplant. Methods. A total of 61 studies (30 kidney, 18 liver, 8 heart, 2 lung/heart-lung, and 3 with mixed recipient samples) were included in a meta-analysis. Average rates of nonadherence to six areas of the regimen, and correlations of potential risk factors with nonadherence, were calculated. Results. Across all types of transplantation, nonadherence to clinic appointments and tests was most prevalent, at 12.9 cases per 100 patients per year (PPY). The immunosuppression nonadherence rate was six cases per 100 PPY. Nonadherence to substance use restrictions, diet, exercise, and other healthcare requirements ranged from 0.6 to 8 cases per 100 PPY. Only the rate of nonadherence to clinic appointments and tests varied by transplant type: heart recipients had the lowest rate (4.6 cases per 100 PPY vs. 12.7–18.8 cases per 100 PPY in other recipients). Older age of the child, family functioning (greater parental distress and lower family cohesion), and the child’s psychological status (poorer behavioral functioning and greater distress) were among the psychosocial characteristics significantly correlated with poorer adherence. These correlations were small to modest in size (r=0.12–0.18). Conclusions. These nonadherence rates provide benchmarks for clinicians to use to estimate patient risk. The identified psychosocial correlates of nonadherence are potential targets for intervention. Future studies should focus on improving the prediction of nonadherence risk and on testing interventions to reduce risk.

Health-related quality of life in nephrology research and clinical practice.

Physical, psychosocial, and lifestyle disturbances, along with physical and emotional symptoms, have been shown to impact the health‐related quality of life (HRQOL) of those dependent on renal replacement therapy. The value of HRQOL measurement as a tool to improve clinical care has been recognized by patients, clinical investigators, and health care providers. The potential importance of HRQOL assessment lies in the additional information it provides and the impact it has on the clinical decision‐making process between a patient and a physician. There remain a multitude of challenges facing renal providers who wish to incorporate HRQOL measurement to improve patient care. These challenges include the clinicians understanding of the conceptual model of HRQOL, the quality of the scientific process that contributed to the current literature on HRQOL, a willingness of the clinician to incorporate HRQOL information into clinical practice, and the logistic difficulties of collecting and applying HRQOL data in a busy practice setting. Arguably, optimizing HRQOL may be the most substantial impact the health care team will have on the person with kidney failure. In order to implement HRQOL assessment at the point of care, providers may consider using computer adaptive testing and scoring algorithms using item response theory, which will allow adequate reliability for interpretation of change among individuals. Moreover, the effective assessment and interpretation of HRQOL will be aided by continued publication of norms, outcomes of randomized controlled trials, and continued experience of investigators and clinicians.