Aspirin prescription and outcomes in hemodialysis patients: the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

We investigated aspirin-prescribing patterns and potential benefits on cardiovascular morbidity and mortality in hemodialysis patients.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

Data included 28,320 randomly selected hemodialysis patients from the Dialysis Outcomes and Practice Patterns Study I and II.

PREDICTOR

Aspirin prescription at study baseline.

OUTCOMES & MEASUREMENTS

Prescription was investigated by means of logistic regression. All-cause mortality, all-cause hospitalization, cardiac event, myocardial infarction, cerebrovascular (CVA), gastrointestinal bleed, transient ischemic attack, and subdural hematoma were examined. Cox regression examined the risk of mortality and hospitalization. All models accounted for facility clustering and demographics and comorbid conditions.

RESULTS

Wide variation was found in aspirin prescription, from 8% in Japan to 41% in Australia and New Zealand. Characteristics significantly associated with increased odds of prescription included coronary artery disease, cerebrovascular disease, diabetes, male sex, nonblack race, peripheral vascular disease, age, hypertension, and absence of gastrointestinal bleeding. Aspirin was associated with decreased risk of stroke in all patients (relative risk [RR], 0.82; P < 0.01) and increased risk of myocardial infarction (RR, 1.21; P = 0.01) and cardiac event (RR, 1.08; P < 0.01) in all patients, with similar results for patients with coronary artery disease. There was no increase in gastrointestinal bleeding.

LIMITATIONS

Observational studies are not protected from biases, despite adjustments. There is potential for aspirin use to be underreported because of its availability without prescription.

CONCLUSIONS

The hypothesis that prescribing aspirin to hemodialysis patients decreases cardiovascular disease risk is not supported. Aspirin might decrease CVA and appears not to increase hemorrhagic risk. This should be an incentive for randomized controlled trials.

Diuretic use, residual renal function, and mortality among hemodialysis patients in the Dialysis Outcomes and Practice Pattern Study (DOPPS)

BACKGROUND

Information about residual renal function (RRF) and outcomes associated with practices of diuretic use in patients with end-stage renal disease is not available worldwide.

METHODS

Diuretic use was investigated in 16,420 hemodialysis patients from the Dialysis Outcomes and Practice Patterns Study, a prospective observational study of hemodialysis patients selected from nationally representative facilities on 3 continents. Logistic regressions were used to investigate associations between diuretic use and patient characteristics. Outcomes of interdialytic weight gain, increased serum potassium and phosphorus levels, and odds of retaining RRF after 1 year were investigated. Cox regression was used to analyze the association between mortality and diuretic use.

RESULTS

Facility diuretic use varied substantially from 0% to 83.9% of patients. Diuretic use decreased sharply after the start of dialysis therapy. Loop diuretic use ranged from 9.2% in the United States to 21.3% in Europe, whereas use within 90 days of starting dialysis therapy ranged from 25.0% in the United States to 47.6% in Japan. Diuretic use was associated with lower interdialytic weight gain and lower odds of hyperkalemia (potassium > 6.0 mmol/L). Patients with RRF on diuretic therapy had almost twice the odds of retaining RRF after 1 year in the study versus patients not on diuretic therapy. Patients administered diuretics had a 7% lower all-cause mortality risk (P = 0.12) and 14% lower cardiac-specific mortality risk (P = 0.03) versus patients not administered diuretics.

CONCLUSION

Variation exists in facility practices of diuretic use. In patients with RRF, there may be benefit associated with continuing diuretic use rather than automatically discontinuing diuretic therapy at dialysis initiation.

Factors associated with health-related quality of life among hemodialysis patients in the DOPPS

OBJECTIVE

To identify modifiable factors associated with health-related quality of life (HRQOL) among chronic hemodialysis patients.

METHODS

Analysis of baseline data of 9,526 hemodialysis patients from seven countries enrolled in phase I of the Dialysis Outcomes and Practice Patterns Study (DOPPS). Using the Kidney Disease Quality of Life Short Form (KDQOL-SF(TM)), we determined scores for 8 generic scale summaries derived from these scales, i.e., the physical component summary [PCS] and mental component summary [MCS], and 11 kidney disease- targeted scales. Regression models were used to adjust for differences in comorbidities and sociodemographic and treatment factors. The Benjamini-Hochberg procedure was used to correct P-values for multiple comparisons.

RESULTS

Unemployment and psychiatric disease were independently and significantly associated with lower scores for all generic and several kidney disease-targeted HRQOL measures. Several other comorbidities, lower educational level, lower income, and hypoalbuminemia were also independently and significantly associated with lower scores of PCS and/or MCS and several generic and kidney disease-targeted scales. Hemodialysis by catheter was associated with significantly lower PCS scores, partially explained by the correlation with covariates.

CONCLUSION

Associations of poorer HRQOL with preventable or controllable factors support a greater focus on psychosocial and medical interventions to improve the well-being of hemodialysis patients.

Sexual dysfunction in dialysis patients treated with antihypertensive or antidepressive medications: results from the DOPPS

BACKGROUND

The relationship between medication prescription and sexual dysfunction (SD) in dialysis patients is unclear.

METHODS

We studied antihypertensive and antidepressive agents prescribed for 7346 patients in the Dialysis Outcomes and Practice Patterns Study phase 1 (DOPPS I) and 8891 patients in DOPPS II. At baseline, DOPPS I patients completed a quality of life survey, including four questions about sexual functioning, from which we created a composite SD scale. DOPPS II patients were asked only one question about SD. We examined predictors of SD with logistic regression, using numerous patient characteristics, comorbid conditions and additional variables.

RESULTS

Reported SD ranged from 66.4% (France) to 84.5% (Spain). The mean composite SD score ranged from 6.4 (Spain) to 7.9 (Germany) (on a 3-15 scale). Peripheral alpha-blockers increased odds of DOPPS I patients having their sex life bothered by end-stage renal disease (ESRD) (OR=1.18), and there were elevated odds of arousal problems with central antagonists, loop diuretics and peripheral alpha-blockers (OR=1.19, 1.24 and 1.29, respectively). Selective serotonin reuptake inhibitors (SSRIs) and benzodiazepines increased odds of problems with enjoyment (OR=1.59 and 1.26, respectively) and arousal (OR=1.70 and 1.24, respectively), and having sex life bothered by ESRD (DOPPS I: OR=1.36 and 1.24; DOPPS II: 1.30 and 1.31, respectively). Vasodilators reduced the odds of sexual enjoyment problems (OR=0.75). Composite SD scores worsened with peripheral alpha-blockers (+0.41), tricyclics (+0.78), SSRIs (+0.80) and benzodiazepines (+0.50), but not with vasodilators (-0.57).

CONCLUSIONS

Awareness of associations between SD and prescribed medications may offer opportunities for intervention.

Mineral metabolism and mortality in patients with chronic kidney disease

Chronic kidney disease is associated with profound alterations in mineral metabolism. A growing body of evidence, based largely on observational studies, indicates that patient mortality is associated with altered mineral metabolism. Evidence is reviewed concerning the association between mortality and high concentrations of serum phosphorus, calcium, calcium-phosphate product, and parathyroid hormone. In addition, mortality may be independently associated with dialysate calcium concentration, type of phosphate binder therapy, and use of vitamin D analogs. Practices related to management of altered mineral metabolism may prove to be a promising means of improving outcomes for patients with chronic kidney disease.

Pruritus in haemodialysis patients: International results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Pruritus affects many haemodialysis (HD) patients. In this study, pruritus and its relationship to morbidity, mortality, quality of life (QoL), sleep quality and patient laboratory measures were analysed in >300 dialysis units in 12 countries.

METHODS

Pruritus data were collected from 18 801 HD patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS) (1996-2004). Analyses were adjusted for age, gender, black race, Kt/V, haemoglobin, serum albumin, albumin-corrected serum calcium, serum phosphorus, 13 comorbidities, depression, years on dialysis, country and facility clustering effects.

RESULTS

Moderate to extreme pruritus was experienced by 42% of prevalent HD patients in DOPPS during 2002/2003. Many patient characteristics were significantly associated with pruritus, but this did not explain the large differences in pruritus between countries (ranging from 36% in France to 50% in the UK) and between facilities (5-75%). Pruritus was slightly less common in patients starting HD than in patients on dialysis >3 months. Pruritus in new end-stage renal disease (ESRD) patients likely results from pre-existing conditions and not haemodialysis per se, indicating the need to understand development of pruritus before ESRD. Patients with moderate to extreme pruritus were more likely to feel drained [adjusted odds ratio (AOR) = 2.3-5.2, P < 0.0001] and to have poor sleep quality (AOR = 1.9-4.1, P < or = 0.0002), physician-diagnosed depression (AOR = 1.3-1.7, P < or = 0.004), and QoL mental and physical composite scores 3.1-8.6 points lower (P < 0.0001) than patients with no/mild pruritus. Pruritus in HD patients was associated with a 17% higher mortality risk (P < 0.0001), which was no longer significant after adjusting for sleep quality measures.

CONCLUSIONS

The pruritus/mortality relationship may be substantially attributed to poor sleep quality. The many poor outcomes associated with pruritus underscore the need for better therapeutic agents to provide relief for the 40-50% of HD patients affected by pruritus.

Incidence and risk factors for hip or other bone fractures among hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study

The available data on bone fractures in hemodialysis (HD) patients are limited to results of a few studies of subgroups of patients in the United States. This study describes the prevalence of hip fractures and the incidence and risk factors associated with hip and other fractures in representative groups of HD facilities (n=320) and patients (n=12 782) from the 12 countries in the second phase of the Dialysis Outcomes and Practice Patterns Study (2002-2004). Among prevalent patients, 2.6% had a prior hip fracture. The incidence of fractures was 8.9 per 1000 patient years for new hip fractures and 25.6 per 1000 for any new fracture. Older age (relative risk (RR)(HIP)=1.91, RR(ANY)=1.33, P<0.0001), female sex (RR(HIP)=1.41, P=0.02; RR(ANY)=1.59, P<0.0001), prior kidney transplant (RR(HIP)=2.35, P=0.04; RR(ANY)=1.76, P=0.007), and low serum albumin (RR(HIP)=1.85, RR(ANY)=1.45, per 1 g/dl lower, P<0.0001) were predictive of new fractures. Elevated risk of new hip fracture was observed for selective serotonin reuptake inhibitors and combination narcotic medications (RR=1.63, RR=1.74, respectively, P<0.05). Several medications were associated with risk of any new fracture: narcotic pain medications (RR=1.67, P=0.02), benzodiazepines (RR=1.31, P=0.03), adrenal cortical steroids (RR=1.40, P<0.05), and combination narcotic medications (RR=1.72, P=0.001). Parathyroid hormone (PTH) levels >900 pg/ml were associated with an elevated risk of any new fracture (RR=1.72, P<0.05) versus PTH 150-300. The results suggest that greater selectivity in prescribing several classes of psychoactive drugs and more efficient treatment of secondary hyperparathyroidism may help reduce the burden of fractures in HD patients.

Starting and withdrawing haemodialysis--associations between nephrologists' opinions, patient characteristics and practice patterns (data from the Dialysis Outcomes and Practice Patterns Study)

BACKGROUND

The incidence and prevalence of haemodialysis vary widely across countries. The variation may be attributable to differences in the incidence of end-stage renal disease and/or in the availability of haemodialysis. Previous studies have identified differences in nephrologists' opinions about the availability of haemodialysis and its appropriateness for patients with comorbidities. We studied the associations between nephrologists' opinions, availability of haemodialysis, patient characteristics and comorbidities, and facilities' withdrawal rates.

METHODS

Most of our analyses used data from 242 haemodialysis units in six countries (France, Germany, Italy, Spain, UK and the USA) in the first phase of the Dialysis Outcomes and Practice Patterns Study (DOPPS I). Opinions about access to and practice patterns in dialysis facilities, measured by the level of agreement with standardized statements, were collected from medical directors and nurse managers. A sub-analysis considered data from corresponding facilities in DOPPS II.

RESULTS

We found wide variations in the prevalence of waiting lists for new dialysis patients (UK 60%; USA 25%; Germany 0%; P < 0.05), in agreement with starting haemodialysis for patients with advanced age, dementia and comorbidities (UK, France < USA < other countries; P < 0.05), and in agreement with withdrawing dialysis (other countries < UK/USA; P < 0.05). The estimated glomerular filtration rate at the start of dialysis was not significantly different in units with waiting lists. Significant associations were found between nephrologists' opinions and the odds of patients being > or =80 years old, and between opinions and the rate and relative risk of withdrawal of haemodialysis. No significant associations were found between opinions and patients' comorbidities or dependency.

CONCLUSION

Differences within and across countries in nephrologists' opinions regarding starting and withdrawing haemodialysis reflect differences in access to haemodialysis and the practice of withdrawal of haemodialysis in their facilities.

Large variations in prescriptions of gastrointestinal medications in hemodialysis patients on three continents: the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Little is known about proton pump inhibitor (PPI) or H(2) receptor antagonist (HA) prescription patterns or regarding use of predictors in hemodialysis patients. Proton pump inhibitor and HA prescribing patterns were investigated in 8628 hemodialysis patients from seven countries enrolled in the prospective, observational Dialysis Outcomes and Practice Patterns Study. Logistic regression examined predictors associated with PPI and HA use, adjusting for age, sex, country, time with end-stage renal disease, medications, 14 comorbid conditions, and the association between the number of comorbid conditions and the prescription of gastrointestinal (GI) medications. In a cross-section from February 1, 2000, 3.4% to 36.9% of patients received an HA and 0.8% to 26.9% took a PPI, depending upon the country. From 1996 to 2001, the prescription of HAs declined while PPI use increased. Facility use of HAs and PPIs ranged from 0% to 94% of patients. H2 receptor antagonist or PPI use was significantly and independently associated with age, narcotic use, corticosteroids, acetaminophen, nonsteroidal anti-inflammatory drugs, tricyclic antidepressants, selective serotonin reuptake inhibitors, coronary artery disease history, cardiovascular diseases other than hypertension or congestive heart failure, peripheral vascular disease, pulmonary disease, and GI bleed. Proton pump inhibitors or HAs were more likely to be prescribed in Italy, Spain, and the United Kingdom than in the United States. The odds of PPI prescription increased if serum phosphorus <5.5 mEq/L or serum albumin <3.5 g/dL. Prescription of GI medications was associated with many comorbidities and use of several medications. Extreme variability of prescription patterns suggests that there is no standard approach in treatment practices.

Longer treatment time and slower ultrafiltration in hemodialysis: Associations with reduced mortality in the DOPPS

Longer treatment time (TT) and slower ultrafiltration rate (UFR) are considered advantageous for hemodialysis (HD) patients. The study included 22,000 HD patients from seven countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS). Logistic regression was used to study predictors of TT > 240 min and UFR > 10 ml/h/kg bodyweight. Cox regression was used for survival analyses. Statistical adjustments were made for patient demographics, comorbidities, dose of dialysis (Kt/V), and body size. Europe and Japan had significantly longer (P < 0.0001) average TT than the US (232 and 244 min vs 211 in DOPPS I; 235 and 240 min vs 221 in DOPPS II). Kt/V increased concomitantly with TT in all three regions with the largest absolute difference observed in Japan. TT > 240 min was independently associated with significantly lower relative risk (RR) of mortality (RR = 0.81; P = 0.0005). Every 30 min longer on HD was associated with a 7% lower RR of mortality (RR = 0.93; P < 0.0001). The RR reduction with longer TT was greatest in Japan. A synergistic interaction occurred between Kt/V and TT (P = 0.007) toward mortality reduction. UFR > 10 ml/h/kg was associated with higher odds of intradialytic hypotension (odds ratio = 1.30; P = 0.045) and a higher risk of mortality (RR = 1.09; P = 0.02). Longer TT and higher Kt/V were independently as well as synergistically associated with lower mortality. Rapid UFR during HD was also associated with higher mortality risk. These results warrant a randomized clinical trial of longer dialysis sessions in thrice-weekly HD.

Improving outcomes for dialysis patients in the international Dialysis Outcomes and Practice Patterns Study

The international Dialysis Outcomes and Practice Patterns Study (DOPPS) is well suited to evaluate levels of deviation from emerging and established guidelines to clinical practice of hemodialysis, over time and by country. The DOPPS can also evaluate whether the target levels that are chosen in the guidelines are in agreement with outcomes such as elevated risk for mortality, hospitalization, and vascular access failure. At a special DOPPS symposium during the 2004 congress of the American Society of Nephrology, the authors presented such findings; key points from that symposium are presented in this article, focusing on vascular access, mineral metabolism, dialysis dose, and anemia management. Although an observational study cannot prove causality, DOPPS suggests large opportunities to improve care and outcomes of dialysis patients. The international perspective of DOPPS assists in the new efforts for international guidelines. Some encouraging trends in recent years are documented in these areas.

Factors associated with "do not resuscitate" orders and rates of withdrawal from hemodialysis in the international DOPPS

BACKGROUND

Worldwide statistics on practice patterns regarding "do not resuscitate" (DNR) orders and patient withdrawal from hemodialysis have not been uniformly collected or analyzed.

METHODS

Using data concerning adult hemodialysis patients randomly selected from 308 representative dialysis facilities in France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States participating in the Dialysis Outcomes and Practice Patterns Study, DNR orders were tabulated at study entry from a prevalent cross-section of patients (N = 8615), using multivariate logistic regression to investigate characteristics associated with DNR status, Cox models to identify risk factors for withdrawal from hemodialysis, and scores from the mental component summary (MCS) and physical component summary (PCS) of the SF-36 to assess health-related quality of life.

RESULTS

The United States had the highest prevalence of DNR orders (7.5%) and rate of withdrawal from hemodialysis (3.5 per 100 patient-years). Significant and independent associations with higher odds ratio (OR) of DNR were observed for older age (OR 1.16 per 10 years higher, P = 0.03) and nursing home residence (OR 2.34, P = 0.003), and with higher relative risk (RR) of withdrawal from dialysis (RR 2.38, P < 0.001). Patients who withdrew from hemodialysis died within a mean of 7.8 days and a median of 6.0 days.

CONCLUSION

The higher prevalence of DNR and rate of withdrawal from hemodialysis in the United States are consistent with its greater legal and cultural emphasis on patient autonomy. By showing characteristics associated with these outcomes, this study contributes to our understanding of why hemodialysis patients request DNR or withdraw from treatment.

CKD Progression and Mortality Among Older Patients With Diabetes

BACKGROUND

Chronic kidney disease (CKD) is clearly associated with an increased risk for adverse outcomes; however, the cumulative impact of renal and cardiac complications in high-risk populations is not known. In addition, little is known about patterns of nephrology care in patients with CKD.

METHODS

We conducted a retrospective longitudinal cohort study assessing CKD prevalence and progression, associations with all-cause mortality, and variations in patterns of nephrology consultation in older patients with diabetes in a vertically integrated health care system.

RESULTS

A total of 12,570 patients within a 7-Veterans Affairs hospital service network in 1998 to 1999 were identified by means of computerized records. Nearly half (48%) were affected with CKD; most had mild to moderate CKD. After an observation period of 3 years, mortality rates in those unaffected with CKD were high (4.7 deaths/100 person-years) and increased substantially with progressive CKD (eg, 20.1 deaths/100 person-years with an estimated glomerular filtration rate [GFR] of 15 to 29 mL/min/1.73 m2 [0.25 to 0.48 mL/s/1.73 m2]). Only 7.2% of patients with CKD had a nephrology visit during the entire 5-year study period. Although visits increased with more advanced CKD, only 32% of patients with an estimated GFR of 15 to 29 mL/min/1.73 m2 had been seen in a nephrology clinic. We also found that nephrology referrals were driven preferentially by elevations in serum creatinine levels, rather than low GFRs.

CONCLUSION

Many in this cohort of older patients with diabetes are affected with CKD. Mortality rates are high, and mortality risks associated with CKD amplify those of other risk factors. Nephrology visits are low and may represent an unexploited resource for improving CKD management. Underrecognition of CKD likely is related to overestimation of kidney function by relying on serum creatinine level in elderly patients.

Predictors and consequences of altered mineral metabolism: the Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Altered mineral metabolism contributes to bone disease, cardiovascular disease, and other clinical problems in patients with end-stage renal disease.

METHODS

This study describes the recent status, significant predictors, and potential consequences of abnormal mineral metabolism in representative groups of hemodialysis facilities (N= 307) and patients (N= 17,236) participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS) in the United States, Europe, and Japan from 1996 to 2001.

RESULTS

Many patients fell out of the recommended guideline range for serum concentrations of phosphorus (8% of patients below lower target range, 52% of patients above upper target range), albumin-corrected calcium (9% below, 50% above), calcium-phosphorus product (44% above), and intact PTH (51% below, 27% above). All-cause mortality was significantly and independently associated with serum concentrations of phosphorus (RR 1.04 per 1 mg/dL, P= 0.0003), calcium (RR 1.10 per 1 mg/dL, P < 0.0001), calcium-phosphorus product (RR 1.02 per 5 mg(2)/dL(2), P= 0.0001), PTH (1.01 per 100 pg/dL, P= 0.04), and dialysate calcium (RR 1.13 per 1 mEq/L, P= 0.01). Cardiovascular mortality was significantly associated with the serum concentrations of phosphorus (RR 1.09, P < 0.0001), calcium (RR 1.14, P < 0.0001), calcium-phosphorus product (RR 1.05, P < 0.0001), and PTH (RR 1.02, P= 0.03). The adjusted rate of parathyroidectomy varied 4-fold across the DOPPS countries, and was significantly associated with baseline concentrations of phosphorus (RR 1.17, P < 0.0001), calcium (RR 1.58, P < 0.0001), calcium-phosphorus product (RR 1.11, P < 0.0001), PTH (RR 1.07, P < 0.0001), and dialysate calcium concentration (RR 0.57, P= 0.03). Overall, 52% of patients received some form of vitamin D therapy, with parenteral forms almost exclusively restricted to the United States. Vitamin D was potentially underused in up to 34% of patients with high PTH, and overused in up to 46% of patients with low PTH. Phosphorus binders (mostly calcium salts during the study period) were used by 81% of patients, with potential overuse in up to 77% patients with low serum phosphorus concentration, and potential underuse in up to 18% of patients with a high serum phosphorus concentration.

CONCLUSION

This study expands our understanding of the relationship between altered mineral metabolism and outcomes and identifies several potential opportunities for improved practice in this area.

Association of predialysis serum bicarbonate levels with risk of mortality and hospitalization in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Experimental and some clinical data suggest that metabolic acidosis contributes to poor nutritional status, a strong predictor for mortality in hemodialysis patients. However, recent cross-sectional studies indicate that severe predialysis metabolic acidosis is associated with a greater normalized protein catabolic rate (nPCR) and greater serum albumin levels. Given this controversy, we analyzed data from the Dialysis Outcomes and Practice Pattern Study (DOPPS) for associations between predialysis serum bicarbonate and albumin concentrations, nPCR, and patient risk for mortality and hospitalization.

METHODS

Data from more than 7,000 representative and randomly selected hemodialysis DOPPS patients from France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States were analyzed. Serum bicarbonate (total CO2 ) levels predialysis were corrected to the midweek interdialytic interval.

RESULTS

The midweek predialysis serum bicarbonate level averaged 21.9 mEq/L (mmol/L) and correlated inversely with nPCR, serum albumin, and serum phosphorus values. Before and after adjusting for 15 comorbidities, nutrition, and equilibrated Kt/V, a U-curve best represented the association between predialysis serum bicarbonate level and risk for mortality or hospitalization. Patients with midweek predialysis serum bicarbonate levels of 20.1 to 21.0 mEq/L (mmol/L) faced the lowest risk for mortality, whereas those with bicarbonate levels of 21.1 to 22.0 mEq/L faced the lowest risk for hospitalization. Both high (>27 mEq/L) and low (< or =17 mEq/L) serum bicarbonate levels were associated with increased risk for mortality and hospitalization.

CONCLUSION

Moderate predialysis acidosis seems to be associated with better nutritional status and lower relative risk for mortality or hospitalization than is observed in patients with normal ranges of midweek predialysis serum bicarbonate concentration (approximately 24 mEq/L) or severe acidosis (<16 mEq/L).

Mineral metabolism and haemoglobin concentration among haemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Bone and mineral metabolism is abnormal in most chronic haemodialysis patients and is associated with a high mortality risk. Because of possible pathogenic links between anaemia and intact parathyroid hormone (iPTH), the present study evaluated associations of mineral metabolism indicators with haemoglobin (Hb).

METHODS

Data were collected from 317 facilities (12 089 haemodialysis patients) in Australia, Belgium, Canada, France, Germany, Italy, Japan, New Zealand, Spain, Sweden, the United Kingdom and the United States by the Dialysis Outcomes and Practice Patterns Study (DOPPS). The major outcome studied was probability of haemodialysis patients having a target Hb, per guidelines, of >/=11 g/dl at baseline. Major predictor variables were patient characteristics and laboratory markers of mineral metabolism: albumin-corrected serum calcium (calcium(Alb)), serum phosphorus (PO(4)) and iPTH. Analyses were adjusted for demographics, 15 comorbidity classes, baseline laboratory values, body mass index, years on dialysis, erythropoietin dose, vitamin D and catheter use, cause of end-stage renal disease and country.

RESULTS

The adjusted odds ratio (AOR) of having Hb >/=11 g/dl was significantly higher (P<0.0001) in patients with higher calcium(Alb) (AOR = 1.32 per 1 mg/dl), higher PO(4) (AOR = 1.08 per 1 mg/dl) and lower iPTH (AOR = 0.96 per 100 pg/ml). Furthermore, 4 month intrapatient changes in Hb concentration were significantly (P<0.0001) related to 4 month changes in calcium(Alb) (0.17 g/dl Hb rise per 1 mg/dl higher calcium(Alb)) and PO(4) (0.11 g/dl Hb rise per 1 mg/dl higher PO(4)). Mean weekly recombinant human erythropoietin (rHuEpo) doses were higher for patients with high PO(4) or iPTH levels, but lower for patients with calcium(Alb) >9.5 mg/dl, after patient mix and Hb concentration adjustments.

CONCLUSIONS

The results of this study indicate that higher serum calcium(Alb) and PO(4) levels are each independently associated with better anaemia control. This relationship is independent of vitamin D use, PTH levels and prescribed rHuEpo dose. Despite this benefit of better anaemia control at higher serum calcium(Alb) and PO(4) concentrations, lower calcium and PO(4) levels, as recommended by the K/DOQI guidelines, should still serve as the long-term goal for HD patients in order to minimize tissue calcification and mortality risk.

HMG-coenzyme a reductase inhibitor use is associated with mortality reduction in hemodialysis patients

BACKGROUND

Cardiovascular disease is the most common cause of mortality in patients with end-stage renal disease. Cardiovascular benefits of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been clearly established in the general population, but not in dialysis patients. This study examined statin prescription patterns and assessed the relationship between statin prescription and clinical outcomes in hemodialysis (HD) patients.

METHODS

Data were analyzed from the Dialysis Outcomes and Practice Patterns Study, a prospective observational study of HD patients randomly selected from representative dialysis facilities in France, Germany, Italy, Spain, the United Kingdom, Japan, and the United States. Predictors of statin prescription were investigated by means of logistic regression. Cox regression models tested the association between statin prescription and risk for mortality and cardiac events, with adjustments for common demographic factors and comorbid conditions.

RESULTS

Statins were prescribed for 11.8% of HD patients overall. Most facilities (81.2%) prescribed statins to less than 20% of their patients. Patients prescribed statins had a 31% lower relative risk for death compared with those not prescribed statins (P < 0.0001). Statins were associated with a 23% lower cardiac mortality risk (P = 0.03) and a 44% lower noncardiac mortality risk (P < 0.0001). At a facility level, prescribing statins was associated with lower overall mortality rate, with a 5% lower risk for every 10% increase in number of patients prescribed statins within the facility (P = 0.02).

CONCLUSION

Statin prescription is associated with reduced mortality in HD patients, providing additional support for the value of statin therapy in this patient group.

Patterns of hepatitis C prevalence and seroconversion in hemodialysis units from three continents: the DOPPS

BACKGROUND

Hepatitis C virus (HCV) remains a problem within hemodialysis units. This study measures HCV prevalence and seroconversion rates across seven countries and investigates associations with facility-level practice patterns.

METHODS

The study sample was from the Dialysis Outcomes and Practice Patterns Study (DOPPS), a prospective, observational study of adult hemodialysis patients randomly selected from 308 representative dialysis facilities in France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States. Logistic regression was used to model odds of HCV prevalence, and Cox regression was used to model time from study entry to HCV seroconversion.

RESULTS

Mean HCV facility prevalence was 13.5% and varied among countries from 2.6% to 22.9%. Increased HCV prevalence was associated with longer time on dialysis, male gender, black race, diabetes, hepatitis B (HBV) infection, prior renal transplant, and alcohol or substance abuse in the previous 12 months. Approximately half of the facilities (55.6%) had no seroconversions during the study period. HCV seroconversion was associated with longer time on dialysis, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), HBV infection, and recurrent cellulitis or gangrene. An increase in highly trained staff was associated with lower HCV prevalence (OR = 0.93 per 10% increase, P= 0.003) and risk of seroconversion (RR = 0.92, P= 0.07). Seroconversion was associated with an increase in facility HCV prevalence (RR = 1.36, P < 0.0001), but not with isolation of HCV-infected patients (RR = 1.01, P= 0.99).

CONCLUSION

There are differences in HCV prevalence and rate of seroconversion at the country and the hemodialysis facility level. The observed variation suggests opportunities for improved HCV outcomes.

Mortality among hemodialysis patients in Europe, Japan, and the United States: case-mix effects

BACKGROUND

The Dialysis Outcomes and Practice Patterns Study is well suited to identify case-mix effects, given its extensive data set. The data set was used to examine the influence of case-mix variables on mortality and the extent to which these variables account for differences in mortality across regions, as well as the prevalence and incidence of hepatitis B and hepatitis C.

METHODS

Demographic and comorbid disease features were determined for 8,615 patients internationally; mortality was recorded for this cohort, plus replacement patients (total n = 16,720), from 1996 to 2002. Mortality was associated with increasing age, nonblack race, coronary artery disease, congestive heart failure, other cardiac disease, diabetes mellitus, peripheral vascular disease, cerebrovascular disease, absence of hypertension, lung disease, cancer, human immunodeficiency virus infection, gastrointestinal bleeding, neurologic disease, psychiatric disease, cellulitis/gangrene, hepatitis C, and smoking.

RESULTS

US patients were slightly older than those in Europe or Japan and had the highest prevalence of diabetes, coronary artery disease, congestive heart failure, peripheral vascular disease, and cerebrovascular disease.

CONCLUSION

Upon adjusting for case-mix to assess mortality across facilities, it was found that regional differences in mortality (highest in the United States and lowest in Japan) and differences across facilities within nations remain after such corrections. It is likely that practice patterns account for some of this variation. Prevalence of hepatitis B virus (HBV) across facilities increased as the number of dialyzing patients per facility increased; risk of HBV seroconversion decreased among facilities using protocols for treatment of patients with HBV infection. Greater employment of staff with at least 2 years of formal nursing training was associated with lower prevalence of hepatitis C virus infection and lower seroconversion risk.

Mortality among hemodialysis patients in Europe, Japan, and the United States: case-mix effects

BACKGROUND

The Dialysis Outcomes and Practice Patterns Study is well suited to identify case-mix effects, given its extensive data set. The data set was used to examine the influence of case-mix variables on mortality and the extent to which these variables account for differences in mortality across regions, as well as the prevalence and incidence of hepatitis B and hepatitis C.

METHODS

Demographic and comorbid disease features were determined for 8,615 patients internationally; mortality was recorded for this cohort, plus replacement patients (total n = 16,720), from 1996 to 2002. Mortality was associated with increasing age, nonblack race, coronary artery disease, congestive heart failure, other cardiac disease, diabetes mellitus, peripheral vascular disease, cerebrovascular disease, absence of hypertension, lung disease, cancer, human immunodeficiency virus infection, gastrointestinal bleeding, neurologic disease, psychiatric disease, cellulitis/gangrene, hepatitis C, and smoking.

RESULTS

US patients were slightly older than those in Europe or Japan and had the highest prevalence of diabetes, coronary artery disease, congestive heart failure, peripheral vascular disease, and cerebrovascular disease.

CONCLUSION

Upon adjusting for case-mix to assess mortality across facilities, it was found that regional differences in mortality (highest in the United States and lowest in Japan) and differences across facilities within nations remain after such corrections. It is likely that practice patterns account for some of this variation. Prevalence of hepatitis B virus (HBV) across facilities increased as the number of dialyzing patients per facility increased; risk of HBV seroconversion decreased among facilities using protocols for treatment of patients with HBV infection. Greater employment of staff with at least 2 years of formal nursing training was associated with lower prevalence of hepatitis C virus infection and lower seroconversion risk.

Magnitude and impact of abnormal mineral metabolism in hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Mineral metabolism has emerged as an important predictor of morbidity and mortality in dialysis patients, independent of bone and muscle concerns. Several expert panels have issued management guidelines for mineral metabolism.

METHODS

The state of mineral metabolism (serum parathyroid hormone [PTH], phosphorus, calcium, and calcium-phosphorus product) was described for representative samples of patients and facilities from 7 countries (France, Germany, Italy, Japan, Spain, United Kingdom, and United States) participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS I, 1996-2001; DOPPS II, 2002-2004).

RESULTS

A relatively modest percentage of patients fell within the guideline range for PTH (21.4% in DOPPS I, 26.2% in DOPPS II), serum phosphorus (40.8%, 44.4%), albumin-corrected serum calcium (40.5%, 42.5%), and calcium-phosphorus product (56.6%, 61.4%). Results were not dramatically different across countries. The majority of patients not within guideline ranges had high serum levels of phosphorus (51.6% in DOPPS I, 46.7% in DOPPS II), calcium (50.1%, 48.6%), and calcium-phosphorus product (43.4%, 38.6%) and low (<150 pg/mL) concentrations of PTH (52.9%, 47.5%). It was rare for patients to fall within recommended ranges for all indicators of mineral metabolism; 23% to 28% fell within guideline for at least 3 measures and only 4.6% to 5.5% of patients were within range for all 4. The risks of all-cause and cardiovascular mortality were directly and independently associated with each of the 4 indicators.

CONCLUSION

The DOPPS provides a useful comparison benchmark for the state of mineral metabolism management of patients with kidney disease; it also affirms the association between mineral metabolism and important patient outcomes.

Screening for depression in hemodialysis patients: Associations with diagnosis, treatment, and outcomes in the DOPPS

BACKGROUND

Depressive symptoms and depression are the most frequent psychologic problems reported by hemodialysis patients. We assessed the prevalence of depressive symptoms and physician-diagnosed depression, their variations by country, and associations with treatment by antidepressants among hemodialysis patients. We also assessed whether depressive symptoms were independently associated with mortality, hospitalization, and dialysis withdrawal.

METHODS

The sample was represented by 9382 hemodialysis patients randomly selected from dialysis centers of 12 countries enrolled in the Dialysis Outcomes and Practice Patterns Study (DOPPS II). Depressive symptoms were assessed by the short version of the Center for Epidemiological Studies Depression Screening Index (CES-D), using > or =10 CES-D score as the cut-off value.

RESULTS

Overall prevalence of physician-diagnosed depression was 13.9%, and percentage of CES-D score > or =10 43.0%. While the smallest prevalence of physician-diagnosed depression was observed in Japan (2.0%) and France (10.6%), the percentage of CES-D score > or =10 in these counties was similar to the whole sample. Patients on antidepressants also varied by country, 34.9% and 17.3% among those with physician-diagnosed depression and CES-D scores > or =10, respectively. In Cox models adjusted for several comorbidities, CES-D scores > or =10 were associated with significantly higher relative risks (RR) of death (RR = 1.42; 95% CI = 1.29 to 1.57), hospitalization (RR = 1.12; 95% CI = 1.03 to 1.22), and dialysis withdrawal (RR = 1.55; 95% CI = 1.29 to 1.85).

CONCLUSION

The data suggest that depression is underdiagnosed and undertreated among hemodialysis patients. CES-D can help identify hemodialysis patients who are at higher risk of death and hospitalization. Interventions should target these patients with the goal to improve survival and reduce hospitalizations.