Risk Equation Determining Unsuccessful Cannulation Events and Failure to Maturation in Arteriovenous Fistulas (REDUCE FTM I)

Fistulas are the preferred permanent hemodialysis vascular access but a significant obstacle to increasing their prevalence is the fistula's high "failure to mature" (FTM) rate. This study aimed to (1) identify preoperative clinical characteristics that are predictive of fistula FTM and (2) use these predictive factors to develop and validate a scoring system to stratify the patient's risk for FTM. From a derivation set of 422 patients who had a first fistula created, a prediction rule was created using multivariate stepwise logistic regression. The model was internally validated using split-half cross-validation and bootstrapping techniques. A simple scoring system was derived and externally validated on 445 different, prospective patients who received a new fistula at five large North American dialysis centers. The clinical predictors that were associated with FTM were aged > or =65 yr (odds ratio [OR] 2.23; 95% confidence interval [CI] 1.25 to 3.96), peripheral vascular disease (OR 2.97; 95% CI 1.34 to 6.57), coronary artery disease (OR 2.83; 95% CI 1.60 to 5.00), and white race (OR 0.43; 95% CI 0.24 to 0.75). The resulting scoring system, which was externally validated in 445 patients, had four risk categories for fistula FTM: low (24%), moderate (34%), high (50%), and very high (69%; trend P < 0.0001). A preoperative, clinical prediction rule to determine fistulas that are likely to fail maturation was created and rigorously validated. It was found to be simple and easily reproducible and applied to predictive risk categories. These categories predicted risk of FTM to be 24, 34, 50, and 69% and are dependent on age, coronary artery disease, peripheral vascular disease, and race. The clinical utility of these risk categories in increasing rates of permanent accesses requires further clinical evaluation.

Catheter-related bacteraemia in haemodialysis patients with HIV infection

BACKGROUND

Tunnelled catheters are used for dialysis in over 25% of haemodialysis (HD) patients and are a major risk factor for bacteraemia. HIV-positive patients may be at particularly increased risk of catheter-related bacteraemia (CRB) due to their immunocompromised state. The present case-controlled study compared catheter-related bacteraemia with HIV-positive and HIV-negative haemodialysis patients.

METHODS

Using a prospective computerized vascular access database, we identified 33 HIV-positive haemodialysis patients who had a tunneled dialysis catheter placed during a 6.5-year period. Their catheter outcomes were compared with those observed in 55 age-, sex- and access date-matched control haemodialysis patients.

RESULTS

The two groups were similar in terms of age, sex, diabetes, hypertension and peripheral vascular disease, but the HIV patients were more likely to be black (94 vs 76%, P=0.03). CRB occurred in 52% of the HIV patients and 49% of the controls (P=0.83). The median infection-free catheter survival was similar in HIV-positive and negative patients (165 vs 119 days, P=0.12). Among patients with CRB, the likelihood of a Gram-negative infection was similar in both groups (18 vs 30%, P=0.37). However, polymicrobial CRB was more likely in HIV patients (41 vs 15%, P=0.049). HIV-positive patients were more likely to be hospitalized for treatment of CRB than HIV-negative patients (29 vs 7%, P=0.05).

CONCLUSION

CRB is equally likely in HIV-positive and control haemodialysis patients. However, CRB is likely to be more severe in HIV-positive patients, as judged from the greater likelihood of polymicrobial infection and of hospitalization.

Needle infiltration of arteriovenous fistulae in hemodialysis: risk factors and consequences

BACKGROUND

Needle infiltration of arteriovenous fistulae is a common problem in US hemodialysis units. This study evaluated the frequency of fistula infiltration, its risk factors, and clinical consequences of this complication.

METHODS

Using a prospective computerized vascular access database, we identified all patients with a major fistula infiltration sufficiently severe to prolong catheter dependence for dialysis. These patients were compared with a control group without fistula infiltration. We also quantified subsequent access outcomes in patients with infiltrations.

RESULTS

During a 5-year period, 47 patients had a major fistula infiltration, representing a 5.2% annual rate. On multiple variable logistic regression analysis, the likelihood of fistula infiltration was associated strongly with patient age (odds ratio, 1.039/1-year increment; 95% confidence interval, 1.016 to 1.062; P = 0.0007). Fistula infiltration was not associated with sex, race, diabetic status, peripheral vascular disease, body mass index, or fistula location. New fistulas (< 6 months in age) were more likely in patients with infiltrations compared with patients without infiltrations (43.5% versus 20.5%; odds ratio, 2.98; 95% confidence interval, 1.61 to 5.54; P = 0.0004). Each major fistula infiltration resulted in a mean of 2.4 diagnostic tests, surgery appointments, or interventions. Fistula thrombosis occurred in 12 patients (26%). Median prolongation of catheter dependence for dialysis in patients with major infiltrations was 97 days.

CONCLUSION

Needle infiltration of fistulae is more common in older patients and with new fistulae. These infiltrations result in numerous procedures, as well as prolongation of catheter dependence for more than 3 months.

Randomized comparison of ultrasound surveillance and clinical monitoring on arteriovenous graft outcomes

Arteriovenous graft thrombosis is a frequent event in hemodialysis patients, and usually occurs in grafts with significant underlying stenosis. Regular surveillance for graft stenosis, with pre-emptive angioplasty of significant lesions, may improve graft outcomes. This prospective, randomized, clinical trial allocated 126 hemodialysis patients with grafts to either clinical monitoring alone (control group) or to regular ultrasound surveillance for graft stenosis every 4 months in addition to clinical monitoring (ultrasound group). The two randomized groups were closely matched with respect to demographic, clinical, and graft characteristics, with the exception of a lower frequency of diabetes in the ultrasound group. The primary outcome was graft survival, and the secondary outcome was thrombosis-free graft survival. The frequency of pre-emptive graft angioplasty was 64% higher in the ultrasound group than in the control group (1.05 vs 0.64 events per patient-year, P<0.001), whereas the frequency of thrombosis was not different (0.67 vs 0.78 per patient-year, P=0.37). The median time to permanent graft failure was similar between the two groups (38 vs 37 months, P=0.93). Likewise, the median time to graft thrombosis or failure did not differ (22 vs 25 months, P=0.33). There was no significant association between diabetes and time to graft failure (P=0.93) or time to graft thrombosis or failure (P=0.88). In conclusion, the addition of regular ultrasound surveillance for graft stenosis to clinical monitoring increases the frequency of pre-emptive angioplasty, but may not decrease the likelihood of graft failure or thrombosis.

Outcomes of thrombosed arteriovenous grafts: Comparison of stents vs angioplasty

The usual radiologic approach to thrombosed grafts is a combination of thrombectomy and angioplasty of the underlying lesion. However, the primary (unassisted) graft patency after thrombectomy is quite poor. We evaluated whether graft patency following thrombectomy is improved by placement of a stent in the stenotic lesion. Using a prospective, computerized vascular access database, we identified 14 patients with thrombosed arteriovenous (A-V) grafts treated with a stent at the venous anastomosis (stent group). The outcomes of these grafts was compared to those observed in 34 sex, age-, and date-matched control patients whose thrombosed A-V grafts were angioplastied (control group). Both groups were comparable in age, sex, race, diabetic status, graft age, and number of previous graft interventions. The immediate technical success, as indicated by the post-procedure graft to systemic pressure ratio, was similar in the stent and control groups (0.33+/-0.16 vs 0.41+/-0.17, P=0.14). The primary graft patency (time from thrombectomy to next intervention) was significantly longer for the stent group (median survival, 85 vs 27 days, P=0.02). Assisted or secondary patency (time from thrombectomy to permanent graft failure) was also longer for the stent group (median survival, 1215 vs 46 days, P=0.049). In conclusion, treatment of thrombosed grafts with a stenosis at the venous anastomosis with a stent results in longer primary and secondary graft survival, as compared to treatment with angioplasty. Stent placement may be a useful treatment modality in a subset of patients with thrombosed A-V grafts and stenosis at the venous anastomosis.

Effect of Change in Vascular Access on Patient Mortality in Hemodialysis Patients

BACKGROUND

Hemodialysis patients using a catheter have a greater mortality risk than those using an arteriovenous (AV) access (fistula or graft). However, catheter-dependent patients also differ from those with an AV access in several clinical features, and these differences may themselves contribute to their excess mortality.

METHODS

The current study evaluates whether a change in vascular access affects risk for mortality in patients enrolled in the Hemodialysis Study. Time-dependent Cox regression was used to relate mortality risk to current type of access and change in access type during the preceding 1 year.

RESULTS

Compared with patients who dialyzed using an AV access at both the beginning and end of the preceding 1-year interval, relative risks for mortality were 3.43 (95% confidence interval [CI], 2.42 to 4.86) in patients who dialyzed with a catheter at both times; 2.38 (95% CI, 1.76 to 3.23) in patients switching from an AV access to a catheter, and 1.37 (95% CI, 0.81 to 2.32) in patients switching from a catheter to an AV access. Change from AV access to a catheter was associated with an antecedent decrease in serum albumin level (odds ratio, 1.25; 95% CI, 1.09 to 1.45 per 0.5 g/dL; P = 0.002), weight loss (odds ratio, 1.14; 95% CI, 1.06 to 1.22 per 2 kg; P < 0.001), and decreases in equilibrated normalized protein catabolic rate (odds ratio, 2.22; 95% CI, 1.41 to 3.57 per 0.25 g/kg/d; P < 0.001) and non-access-related hospitalization (odds ratio, 1.19; 95% CI, 1.06 to 1.32 per 1 additional hospitalization over 4 months; P = 0.002). Change from a catheter to AV access was predicted by only the antecedent non-access-related hospitalization rate (odds ratio, 0.93; 95% CI, 0.87 to 0.97 per 1 additional hospitalization over 4 months; P < 0.001).

CONCLUSION

Change from a catheter to AV access is associated with a substantial decrease in mortality risk.

Outcomes of tunneled femoral hemodialysis catheters: Comparison with internal jugular vein catheters

BACKGROUND

Tunneled femoral vein dialysis catheters are used as a last resort when all other options for a permanent vascular access or thoracic central vein catheter have been exhausted. There is little published literature on the complications or outcomes of tunneled femoral catheters.

METHODS

Using a prospective, computerized vascular access database, we identified all tunneled femoral dialysis catheters placed at the University of Alabama at Birmingham during a five-year period. The clinical features, catheter patency, and complications in these patients were compared to those observed in a group of sex-, age-, and date-matched control patients with tunneled internal jugular vein dialysis catheters.

RESULTS

During the study period, 27 patients received a tunneled femoral dialysis catheter, accounting for 1.9% of all tunneled catheters placed. Only 7 patients (26%) were able to convert to a new permanent dialysis access. The primary catheter patency (time from placement to exchange) was substantially shorter for femoral catheters than for internal jugular dialysis catheters (median survival, 59 vs. >300 days, P < 0.0001). Infection-free survival was similar for both groups (P= 0.66). Seven patients with femoral catheters (or 26%) developed an ipsilateral deep vein thrombosis, but catheter use was possible with anticoagulation.

CONCLUSION

Tunneled femoral dialysis catheters have a substantially shorter primary patency, but a similar risk of catheter-related bacteremia, as compared with internal jugular vein catheters. An ipsilateral lower extremity deep vein thrombosis occurs commonly after placement of a femoral dialysis catheter, but does not preclude continued catheter use.

Association of achieved dialysis dose with mortality in the hemodialysis study: an example of "dose-targeting bias"

In the intention-to-treat analysis of the Hemodialysis Study, all-cause mortality did not differ significantly between the high versus standard hemodialysis dose groups. The association of mortality with delivered dose within each of the two randomized treatment groups was examined, and implications for observational studies were considered. Time-dependent Cox regression was used to relate the relative risk (RR) for mortality to the running mean of the achieved equilibrated Kt/V (eKt/V) over the preceding 4 mo. eKt/V was categorized by quintiles within each dose group. Analyses were controlled for case-mix factors and baseline anthropometric volume. Within each randomized dose group, mortality was elevated markedly when achieved eKt/V was in the lowest quintile (RR, 1.93; 95% confidence interval [CI], 1.40 to 2.66; P < 0.0001 in the standard-dose group; RR, 2.04; 95% CI, 1.50 to 2.76; P < 0.0001 in the high-dose group; RR relative to the middle quintiles). The mortality rate in the lowest eKt/V quintile of the high-dose group was higher than in the full standard-dose group (RR, 1.59; 95% CI, 1.29 to 1.96; P < 0.0001). Each 0.1 eKt/V unit below the group median was associated with a 58% higher mortality in the standard-dose group (P < 0.001) and a 37% higher mortality in the high-dose group (P < 0.001). The magnitude of these dose-mortality effects was seven- to 12-fold higher than the upper limit of the 95% CI from the intention-to-treat analysis. The effects were attenuated in lagged analyses but did not disappear. When dialysis dose is targeted closely, as under the controlled conditions of the Hemodialysis Study, patients with the lowest achieved dose relative to their target dose experience markedly increased mortality, to a degree that is not compatible with a biologic effect of dose. The possibility of similar (albeit smaller) biases should be considered when analyzing observational data sets relating mortality to achieved dose of dialysis.

Tunneled Catheters in Hemodialysis Patients: Reasons and Subsequent Outcomes

BACKGROUND

Reducing the use of tunneled catheters in hemodialysis patients requires concerted efforts to convert them to a usable permanent vascular access. The goal of this study is to evaluate the reasons for tunneled catheter use in our prevalent hemodialysis population and the success in converting them to a permanent vascular access.

METHODS

We identified all catheter-dependent hemodialysis patients at our center on a single date. These patients were followed up prospectively during a 1-year period to evaluate access procedures and conversion to permanent access use.

RESULTS

Of 458 prevalent hemodialysis patients, 108 patients (23.6%) were dialyzing through cuffed tunneled catheters: 18.5% had no further options for creation of a permanent vascular access, 28.7% had an immature access, 43.5% had access placement pending, and 9.2% had repeatedly refused access surgery. For 78 catheter-dependent patients (excluding patients with no access options and those who refused permanent access surgery), the likelihood of using a permanent access was 53% by 6 months and 80% by 1 year. In patients with an immature access, 50% were using a permanent access at 3 months, and 80%, at 6 months. Of patients with access surgery pending, 45% had access surgery performed within 3 months, and 70%, at 6 months. Finally, of all patients, the likelihood of catheter-related bacteremia was 48% at 6 months. On multivariable analysis, only duration of catheter dependence predicted subsequent use of a permanent access (hazard ratio, 3.11; 95% confidence interval, 1.70 to 5.68; P = 0.0002) for catheter dependence less than versus greater than 6 months.

CONCLUSION

Almost one quarter of our hemodialysis population is catheter dependent. Despite concerted efforts, there remain very long delays in achieving a usable permanent access, attributable to delays in both surgical access placement and access maturation. In the interim, this patient population developed a high frequency of catheter-related bacteremia.

Turbulent Flow Evaluation of the Venous Needle During Hemodialysis

Arteriovenous (AV) grafts and fistulas used for hemodialysis frequently develop intimal hyperplasia (IH) at the venous anastomosis of the graft, leading to flow-limiting stenosis, and ultimately to graft failure due to thrombosis. Although the high AV access blood flow has been implicated in the pathogenesis of graft stenosis, the potential role of needle turbulence during hemodialysis is relatively unexplored. High turbulent stresses from the needle jet that reach the venous anastomosis may contribute to endothelial denudation and vessel wall injury. This may trigger the molecular and cellular cascade involving platelet activation and IH, leading to eventual graft failure. In an in-vitro graft/needle model dye injection flow visualization was used for qualitative study of flow patterns, whereas laser Doppler velocimetry was used to compare the levels of turbulence at the venous anastomosis in the presence and absence of a venous needle jet. Considerably higher turbulence was observed downstream of the venous needle, in comparison to graft flow alone without the needle. While turbulent RMS remained around 0.1m∕s for the graft flow alone, turbulent RMS fluctuations downstream of the needle soared to 0.4–0.7m∕s at 2 cm from the tip of the needle and maintained values higher than 0.1m∕s up to 7–8 cm downstream. Turbulent intensities were 5–6 times greater in the presence of the needle, in comparison with graft flow alone. Since hemodialysis patients are exposed to needle turbulence for four hours three times a week, the role of post-venous needle turbulence may be important in the pathogenesis of AV graft complications. A better understanding of the role of needle turbulence in the mechanisms of AV graft failure may lead to improved design of AV grafts and venous needles associated with reduced turbulence, and to pharmacological interventions that attenuate IH and graft failure resulting from turbulence.

The spectrum of infection-related morbidity in hospitalized haemodialysis patients

BACKGROUND

Infection is a common cause of mortality and morbidity in haemodialysis patients. Few prospective studies have examined the clinical consequences of infection-related hospitalizations in haemodialysis patients or the risk factors predictive of clinical outcomes.

METHODS

The outcomes of all first infection-related hospitalizations of patients enrolled in the HEMO Study were categorized in terms of mortality, requirement for intensive care unit (ICU) stay and length of hospitalization. In addition, the association of hospitalization outcomes with clinical and laboratory parameters was evaluated.

RESULTS

Among the 783 first infection-related hospitalizations, 57.7% had a severe outcome (death, ICU stay or hospitalization >/=7 days). The likelihood of a severe outcome increased with patient age (P<0.0001) and with decreased serum albumin (P<0.001). The frequency of a severe outcome varied greatly by infectious disease category (P<0.001), being highest for cardiac infections (95.6%) and infection of unknown source (68.4%), and lowest for urinary tract infections (35.5%) and access-related infections (43.8%). On multivariate analysis, hospitalization outcome was independently associated with patient age, serum albumin and disease category, but not with the randomized Kt/V or flux, gender, race or diabetic status.

CONCLUSION

In summary, infection-related hospitalizations are associated with substantial morbidity. Patient age, serum albumin and infectious disease category are independently correlated with the hospitalization outcome, and can be used to estimate the likelihood of serious outcomes at the time of hospital admission.

Vascular access stenosis: comparison of arteriovenous grafts and fistulas

BACKGROUND

Vascular access stenosis is a frequent problem in hemodialysis patients. There is little published literature comparing the features of stenosis between arteriovenous fistulas and grafts, relative outcomes of elective angioplasty, and clinical factors predictive of access patency after angioplasty.

METHODS

Prospective data were collected for all patients referred for a fistulogram during a 2-year period because of suspected access stenosis. Angioplasty was performed if there was greater than 50% stenosis. For each procedure, we recorded the number and location of stenotic lesions, degree of stenosis (on a scale of 1 to 4), and ratio of access to systemic systolic pressure. All subsequent access procedures were tracked prospectively to calculate intervention-free access survival. Multivariable analysis was used to evaluate clinical factors affecting access patency after angioplasty.

RESULTS

Five hundred forty-three fistulograms were obtained: 358 in grafts and 185 in fistulas. The likelihood of finding a significant stenosis was substantially lower in fistulas than grafts (39.4% versus 68.7%; P < 0.001). Among patients with a significant stenosis, those with fistulas were less likely to have 2 or more stenotic lesions (12.5% versus 33.1%; P < 0.001). After angioplasty, degree of stenosis (1.35 +/- 0.70 versus 1.23 +/- 0.52) and access to systemic pressure ratio (0.34 +/- 0.15 versus 0.32 +/- 0.14) were similar between fistulas and grafts. Intervention-free survival was similar for fistulas and grafts (median survival, 7.5 versus 6.2 months; P = 0.36). Using multivariable stepwise proportional hazard regression analysis, only female sex, residual access stenosis, and postangioplasty access pressure ratio greater than 0.4 significantly predicted access survival (P = 0.0006).

CONCLUSION

The positive predictive value of clinical evaluation for access stenosis is substantially lower for fistulas than grafts. The technical success of angioplasty and subsequent primary patency are similar for fistulas and grafts. Finally, female sex, residual stenosis, and high postprocedure access pressure ratio are each predictive of shorter access patency after elective angioplasty.

Dialysis catheter-related bacteremia: treatment and prophylaxis

Catheter-related bacteremia is a major cause of morbidity among hemodialysis patients. This article reviews the medical literature regarding the treatment and prophylaxis of catheter-related bacteremia. Bacterial biofilm that forms in the catheter lumen is the source of catheter-related bacteremia. Treatment with systemic antibiotics alone fails to definitively eradicate the infection in most patients. Catheter-related bacteremia can be managed by either catheter removal with delayed placement of a new catheter or exchange of the infected catheter with a new catheter over a guidewire. More recent studies suggested that instillation of an antibiotic-anticoagulant lock into the catheter lumen, as an adjunct to systemic antibiotic therapy, can cure approximately two thirds of catheter-related bacteremias without requiring catheter replacement. The frequency of catheter-related bacteremia may be reduced by using tunneled, rather than nontunneled, dialysis catheters and strict aseptic technique. In addition, several pharmacological measures may be useful for prophylaxis against catheter-related bacteremia. These include application of an antimicrobial ointment (mupirocin or polysporin [Pfizer, New York, NY]) to the catheter exit site or instillation of an antimicrobial solution (gentamicin or taurolidine) into the catheter lumen. Subcutaneous dialysis devices do not reduce the frequency of catheter-related bacteremia unless an antimicrobial solution is instilled into the device. The development and widespread adoption of effective approaches to the treatment and prophylaxis of catheter-related bacteremia will dramatically reduce the morbidity and economic burden associated with this complication.

Special Article: Improving Outcomes in CKD and ESRD Patients: Carrying the Torch from Training to Practice

Practicing nephrologists are spending more time caring for end-stage renal disease (ESRD) and chronic kidney disease (CKD) patients. Despite this focus, and considerable advances in the understanding of those aspects of care that impact on clinical outcomes, morbidity, mortality, and quality of life for these patients has not improved substantially over the past decade. One of the possible explanations for this lack of progress is the structure of current nephrology training programs, where ESRD and CKD patient care is not emphasized. To address this issue, we developed a short preceptorship for second-year nephrology fellows, including didactic lectures and workshops. Of 67 participating fellows, 50% were from programs offering 3 or fewer months of exposure to outpatient hemodialysis, and 25% reported no exposure to peritoneal dialysis. Of more concern, 25% reported no "official rounds" with an attending nephrologist on dialysis patients. If nephrologists are to take their appropriate place as leaders of the care delivery team, nephrology fellowships must be restructured with appropriate emphasis placed on the comprehensive care of ESRD and CKD patients.

Association of pelvic arterial calcification with arteriovenous thigh graft failure in haemodialysis patients

BACKGROUND

Arterial calcification is a common problem in patients with chronic kidney disease, and has been associated with adverse clinical outcomes. The goal of the present study was to evaluate whether pelvic artery calcifications are associated with technical failure of arteriovenous thigh grafts in haemodialysis patients.

METHODS

From 1 January 1999 to 30 June 2002, thigh grafts were placed in 54 haemodialysis patients who had exhausted all options for permanent vascular access in the upper extremities. Perioperative computed tomography (CT) of the abdomen and pelvis was obtained in 32 of the patients for diagnostic purposes unrelated to vascular access planning. Two radiologists, who were blinded to the graft outcomes, scored the vascular calcifications on CT of the distal aorta, common iliac, external iliac and common femoral arteries on a semi-quantitative 5-point scale. The association between technical graft failure (inability to complete the anastomosis) and the vascular calcification score was analysed.

RESULTS

There was a high inter-observer agreement in scoring vascular calcification (kappa = 0.801). Among 26 patients with absent or mild pelvic arterial calcifications (grade 1-2) on CT, none (0%) experienced technical graft failure. In contrast, three of six patients (50%) with moderate to severe calcification (grade 3-5) had technical graft failures (P = 0.004 by Fisher's exact test). The cumulative 1 year graft patency was lower in the group with grade 3-5 calcification (33 vs 81%, P = 0.09). The two groups were similar in age, gender, race, diabetes, duration of dialysis, serum calcium, serum phosphorus and serum parathyroid hormone.

CONCLUSION

There is a strong association between pelvic artery calcifications and technical failure of thigh grafts. The presence of moderate to severe vascular calcification is predictive of poor cumulative 1 year graft patency.

Associations with predialysis vascular access management

BACKGROUND

The Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines encourage increasing the proportion of arteriovenous fistulae among incident hemodialysis patients. Achieving optimal outcomes requires predialysis out-patient follow-up by a nephrologist, predialysis placement of a vascular access, and adequate maturation of the vascular access.

METHODS

We assessed the effect of clinical factors on predialysis vascular access management in all incident hemodialysis patients at a single institution during a 2-year period.

RESULTS

Of 157 patients initiating dialysis therapy from January 1, 2001, to December 31, 2002, a total of 73.2% had predialysis follow-up by a nephrologist, 46.5% had predialysis vascular access surgery, and 35.0% initiated their first dialysis session with a permanent access. Among patients using a permanent access on their first dialysis session, 67.3% used a fistula. Patients with diabetes were more likely than those without diabetes to have predialysis nephrology follow-up (81.5% versus 61.5%; P = 0.005), undergo predialysis vascular access surgery (56.5% versus 32.3%; P = 0.003), and initiate their first dialysis session with a fistula or graft (43.5% versus 23.1%; P = 0.008). Duration of predialysis nephrology follow-up was similar between patients with and without diabetes (median, 412 versus 300 days; P = 0.27). Patient age, sex, and race were not predictive of predialysis access management.

CONCLUSION

Despite attempts to follow the K/DOQI guidelines, 65% of incident hemodialysis patients initiated their first dialysis treatment with a catheter. Patients with diabetes were significantly more likely to have predialysis follow-up by a nephrologist and thus more likely to initiate their first dialysis session with a permanent access. Emphasis on early referral of patients with chronic kidney disease without diabetes to nephrologists may increase fistula use among incident hemodialysis patients.

Dialysis dose and the effect of gender and body size on outcome in the HEMO Study

BACKGROUND

Gender and body size have been associated with survival in hemodialysis populations. In recent observational studies, overall mortality was similar in men and women and higher in small patients. The effect of dialysis dose in each of these subgroups has not been tested in a clinical trial.

METHODS

The HEMO Study was a controlled trial of dialysis dose and membrane flux in 1846 hemodialysis patients followed up for 6.6 years in 15 centers throughout the United States. We examined the effect of dialysis dose on mortality and on selected secondary outcomes in subgroups of patients.

RESULTS

Adjusting for age only, overall mortality was lower in patients with higher body weight (P < 0.001), higher body mass index (P < 0.001), and higher body water content determined by the Watson formula (Vw) (P < 0.001), but was not associated with gender (P= 0.27). The RR of mortality comparing the high dose with the standard dose group was related to gender (P= 0.014). Women randomized to the high dose had a lower mortality rate than women randomized to the standard dose (RR = 0.81, P= 0.02), while men randomized to the high dose had a nonsignificant trend for a higher mortality rate than men randomized to the standard dose (RR = 1.16, P= 0.16). Analysis of both genders combined showed no overall dose effect (R = 0.96, P= 0.52), as reported previously. Vw was greater than 35 L in 84% of men compared with 17% of women. However, the RR of mortality for the high versus standard dose remained lower in women than in men after adjustment for the interaction of dose with Vw or with other size parameters, including weight and body mass index. Conversely, the dose effect was not significantly related to size parameters after controlling for the relationship of the dose comparison with gender.

CONCLUSION

The data suggest that mortality and morbidity might be reduced by increasing the dialysis dose above the current standard in women but not in men. This effect was not explained by differences between men and women in age, race, or in several indices of body size. Because multiple comparisons were considered in this analysis, the role of gender on the effect of dialysis dose is suggestive and invites further study.