The American Journal of Managed Care August 2009
Cost Comparison of Peritoneal Dialysis Versus Hemodialysis in End-Stage Renal Disease
Patients with end-stage renal disease who began peritoneal dialysis had lower 1-year hospitalization rates and lower total healthcare costs than those who began therapy with hemodialysis.
The median (IQR) total per-patient healthcare costs were $43,510 higher among HD patients than among PD patients over 12 months ($173,507 [$98,706-$335,719] vs $129,997 [$73,212-$207,578], P = .03). The median (IQR) per-patient inpatient costs were $39,851 ($6089-$140,125) for HD patients versus $651 ($0-$40,591) for PD patients (P <.01); the corresponding values for other services were $73,392 ($24,087-$101,992) versus $70,642 ($17,652-$96,770) for outpatient office visits (P = .53), $360 ($0-$1340) versus $0 ($0-$135) for ED visits (P = .29), $2454 ($0-$6483) versus $2750 ($0-$8591) for outpatient (ie, retail) pharmacy (P = .28), and $14,097 ($6987-$49,320) versus $16,229 ($4192-$37,867) for all other services (P = .47). The difference in the total per-patient healthcare costs over 12 months was $80,709 (mean [95% CI], $263,001 [$200,925-$334,588] vs $182,292 [$129,942-$253,090]; P = .04). The mean (95% CI) per-patient inpatient costs were $140,633 ($81,752-$211,574)
for HD patients and $79,175 ($28,522-$144,682) for PD patients (P = .08); the corresponding values for other services were $81,046 ($62,626-$101,583) versus $70,798 ($55,490-$86,781) for outpatient visits (P = .48), $1395 ($731-$2204) versus $848 ($380-$1491) for ED visits (P = .27), $4196 ($2774-$5805) versus $6679 ($4036-$10,133) for outpatient pharmacy (P = .15), and $35,731 ($24,054-$47,886) versus $24,792 ($17,152-$33,701) for all other services (P = .17).
In the absence of head-to-head clinical trials, which may never be conducted, observational studies such as ours may be the only means of comparing healthcare utilization and costs in patients beginning dialysis with HD versus PD. Findings from our study suggest that privately insured patients who initiate dialysis with PD have significantly lower risks of hospitalization and lower total costs of care over 12 months than HD patients of similar demographic and clinical characteristics. While comparatively few dialysis patients began therapy with PD (only about 12% in our study), it has been estimated that 76% to 93% of patients beginning dialysis have no contraindications and could receive either modality.13 Our study results suggest that expanded use of PD in lieu of HD may yield substantial economic benefits to private payers.
Prior analyses of Medicare enrollees have consistently reported lower healthcare costs among patients who initiated dialysis with PD rather than HD, although the magnitude of differences reported by others is less than we observed. (Medicare typically pays less for services than private insurers because of the ability [ie, market power] of the former to dictate payment rates.) The 2006 US Renal Data System Annual Data Report14 noted that the mean annual per-patient costs of dialysis (all modalities) were $67,000 for Medicare patients and $180,000 for patients covered by private health insurance (“Employer Group Health Plans”). In 2005, for example, annual per-patient Medicare expenditures related to vascular access were $52,734 for patients with PD catheters and approximately $65,509 for patients with HD access points ($58,294, $67,479, and $74,963 for patients with arteriovenous fistulas, grafts, and catheters, respectively).4 Shih and colleagues15 examined Medicare expenditures over a 3-year period following initiation of dialysis among 3423 patients with incident ESRD identified in the US Renal Data System. After adjustment for differences in patient characteristics (eg, age, sex, race/ethnicity, comorbidities, and primary cause of ESRD), the estimated total annual Medicare expenditures were reported to be $11,446 lower for PD patients than for HD patients ($56,807 vs $68,253, P <.001). Bruns and colleagues16 identified 148 patients receiving PD (n = 35) or HD (n = 113) at the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, between July 1, 1994, and June 30, 1995. The unadjusted mean annual perpatient costs were $17,920 lower among those who received PD ($45,420 vs $63,340 for HD, significance not reported). Peritoneal dialysis has also been reported to be less expensive than HD in non-US populations with ESRD.17-22
Historically, patients beginning dialysis with PD have been described as healthier on average than those initiating treatment with HD in terms of the number and severity of reported comorbidities.23,24 In our study, PD patients were younger than HD patients, and fewer of them had a history (based on attributable healthcare encounters) of congestive heart failure or hypertension. We attempted to control for differences in patient characteristics by propensity matching patients on the basis of pretreatment comorbidities and healthcare utilization and costs. Although no significant pretreatment differences were noted between PD patients and HD patients in the matched sample, the database is limited in terms of the clinical information it contains. Accordingly, the degree to which our findings may reflect residual confounding is unknown (ie, factors that continue to differ between the 2 groups, despite matching, other than initial dialysis modality that also are related to study outcomes).
Differences in the total healthcare costs between PD patients and HD patients in our study were largely attributable to differences in the cost of inpatient care. Although HD patients typically have higher medication costs than PD patients because of their increased use of erythropoietin- stimulating agents (ESAs) (in 2005, the Medicare ESRD program spent about $2 billion on ESAs, most of which was received by HD patients4,25), we did not observe a similar difference in our study, most likely because claims for ESAs administered in office or clinic settings may be bundled with other services and not explicitly noted. To the extent that bundling actually occurs, we would not be able to determine the services (including ESA administration) that were actually rendered in the office and clinic settings. Unfortunately, the extent to which bundling actually occurs—and its possible effect on our findings—is unknown. However, the percentage of patients in our study who received ESAs in the period before dialysis (ie, 16%-17%) falls within the range (11%-31%) reported in prior studies6,26 of a similar nature that also were based on healthcare claims data.
As already noted, PD was the initial dialysis modality for only about 12% of patients in our study. In prior research, 7% to 27% of patients with ESRD in the United States have been reported to initiate dialysis with PD.2,14-16,23,24,27 Using data from the US Renal Data System, Mehrotra and colleagues13 reported that the use of PD among patients with incident ESRD declined from 11% during 1996-1997 to 7% during 2002-2003; the use of PD has continued to decline and was reported to be 6.7% in 2005.4 Several reasons have been postulated for these low rates of use, including lack of nephrologist training on PD techniques, late patient referral to nephrologists, economic incentives associated with HD (eg, reimbursement mechanisms for iron supplementation and ESAs), lack of investment in infrastructure related to PD, poor patient education concerning dialysis options before initiation of therapy, and increased availability of HD during the early morning, late evening, and overnight hours.2,5,13,18,28,29 Unfortunately, we could not address these issues in our study.
Our study has some additional limitations. First, given limitations of the database, we were unable to validate the algorithms that we used to identify PD patients and HD patients. By requiring that patients have at least claims with codes specific to PD or HD, we believe that the possibility of misclassification based on coding error was limited. Furthermore, we limited the possibility that patients who receive dialysis on a temporary basis only (eg, for acute renal failure) were inadvertently included in our study sample by requiring that patients have evidence of receipt of dialysis or a kidney transplant (indicative of ESRD) over a period of at least 3 months following the index date for dialysis. Nonetheless, the precise magnitude of misclassification bias is unknown.
Second, we tallied healthcare utilization and costs using an “intent-to-treat” approach (ie, in relation to the first treatment received). Therefore, patients who switched from HD to PD or, more likely, from PD to HD would have levels of utilization and cost that presumably would be reflective of both modalities. Prior research has indicated that 25% to 33% of PD patients switch to HD compared with only 3% to 5% of HD patients who switch to PD.15,30 In their analyses of patients beginning dialysis with PD versus HD, Shih et al15 reported that PD patients who did not switch to HD averaged $48,446 in multivariate-adjusted annual Medicare expenditures versus $68,531 for all PD patients combined (ie, irrespective of switching status); similar figures for HD were $68,209 versus $72,189 (all values are in 2004 US dollars). Therefore, our findings may represent an underestimate of the true difference in cost between the 2 modalities; however, the magnitude of underestimation is unknown.
Additional benefits have been hypothesized for PD versus HD, including flexible scheduling, fewer needlesticks (preserving arteriovenous access sites for future HD and minimizing the risk of blood-borne infections), and better preservation of residual renal function.2 Moreover, PD has been associated with greater patient satisfaction with dialysis care and with a reduced burden of kidney disease.31-33 However, limitations of the database precluded us from addressing any of these issues in our study.
In conclusion, after matching our patient groups on several pretreatment characteristics, we found that patients beginning PD were significantly less likely than those initiating treatment with HD to be hospitalized over 12 months and that they had significantly lower total healthcare costs over this period. To the extent that our findings reflect differences in outcomes associated with choice of dialysis modality rather than differences in patient characteristics that we could not account for, the results may be of significant interest to private-sector insurers.
Author Affiliations: Policy Analysis, Inc (AB, JE, GO), Brookline, MA; and Baxter Healthcare Corporation (GWI, SKB), McGraw Park, IL.
Funding Source: Funding for this research was provided by Baxter Healthcare Corporation, McGraw Park, IL.
Author Disclosure: Mr Berger, Dr Edelsberg, and Dr Oster are employees of a contract research organization that received payment for developing the manuscript as part of an ongoing engagement with the study’s sponsor. Mr Inglese and Dr Bhattacharyya are employees of Baxter Healthcare Corporation, the sponsor of the study, and report owning stock in that company.
Authorship Information: Concept and design (AB, JE, GWI, SKB, GO); analysis and interpretation of data (AB, JE, GWI, SKB, GO); drafting of the manuscript (AB, JE, GWI, SKB, GO); critical revision of the manuscript for important intellectual content (AB, JE, GWI, SKB, GO); statistical analysis (AB, GO); obtaining funding (AB, JE, GWI, SKB, GO); administrative, technical, or logistic support (AB, JE, GWI, SKB, GO); and supervision (AB, GO).
Address correspondence to: Gerry Oster, PhD, Policy Analysis, Inc, Four Davis Ct, Brookline, MA 02445. E-mail: firstname.lastname@example.org.
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