Walk-in clinic patient characteristics and utilization patterns in Ontario, Canada: a cross-sectional study

BACKGROUND

Walk-in clinics are common in North America and are designed to provide acute episodic care without an appointment. We sought to describe a sample of walk-in clinic patients in Ontario, Canada, which is a setting with high levels of primary care attachment.

METHODS

We performed a cross-sectional study using health administrative data from 2019. We compared the sociodemographic characteristics and health care utilization patterns of patients attending 1 of 72 walk-in clinics with those of the general Ontario population. We examined the subset of patients who were enrolled with a family physician and compared walk-in clinic visits to family physician visits.

RESULTS

Our study found that 562 781 patients made 1 148 151 visits to the included walk-in clinics. Most (70%) patients who attended a walk-in clinic had an enrolling family physician. Walk-in clinic patients were younger (mean age 36 yr v. 41 yr, standardized mean difference [SMD] 0.24), yet had greater health care utilization (moderate and high use group 74% v. 65%, SMD 0.20) than the general Ontario population. Among enrolled Ontarians, walk-in patients had more comorbidities (moderate and high count 50% v. 45%, SMD 0.10), lived farther from their enrolling physician (median 8 km v. 6 km, SMD 0.21) and saw their enrolling physician less in the previous year (any visit 67% v. 80%, SMD 0.30). Walk-in encounters happened more often after hours (16% v. 9%, SMD 0.20) and on weekends (18% v. 5%, SMD 0.45). Walk-in clinics were more often within 3 km of patients' homes than enrolling physicians' offices (0 to < 3 km: 32% v. 22%, SMD 0.21).

INTERPRETATION

Our findings suggest that proximity of walk-in clinics and after-hours access may be contributing to walk-in clinic use among patients enrolled with a family physician. These findings have implications for policy development to improve the integration of walk-in clinics and longitudinal primary care.

Characteristics and practice patterns of family physicians who provide home visits in Ontario, Canada: a cross-sectional study

BACKGROUND

Physician home visits are essential for populations who cannot easily access office-based primary care. The objective of this study was to describe the characteristics, practice patterns and physician-level patient characteristics of Ontario physicians who provide home visits.

METHODS

This was a retrospective cross-sectional study, based on health administrative data, of Ontario physicians who provided home visits and their patients, between Jan. 1, 2019, and Dec. 31, 2019. We selected family physicians who had at least 1 home visit in 2019. Physician demographic characteristics, practice patterns and aggregated patient characteristics were compared between high-volume home visit physicians (the top 5%) and low-volume home visit physicians (bottom 95%).

RESULTS

A total of 6572 family physicians had at least 1 home visit in 2019. The top 5% of home visit physicians (n = 330) performed 58.6% of all home visits (n = 227 321 out of 387 139). Compared with low-volume home visit physicians (n = 6242), the top 5% were more likely to be male and practise in large urban areas, and rarely saw patients who were enrolled to them (median 4% v. 87.5%, standardized mean difference 1.12). High-volume physicians' home visit patients were younger, had greater levels of health care resource utilization, resided in lower-income and large urban neighbourhoods, and were less likely to have a medical home.

INTERPRETATION

A small subset of home visit physicians provided a large proportion of home visits in Ontario. These home visits may be addressing a gap in access to primary care for certain patients, but could be contributing to lower continuity of care.

Characteristics and Health Care Use of Patients Attending Virtual Walk-in Clinics in Ontario, Canada: Cross-sectional Analysis

BACKGROUND

Funding changes in response to the COVID-19 pandemic supported the growth of direct-to-consumer virtual walk-in clinics in several countries. Little is known about patients who attend virtual walk-in clinics or how these clinics contribute to care continuity and subsequent health care use.

OBJECTIVE

The objective of the present study was to describe the characteristics and measure the health care use of patients who attended virtual walk-in clinics compared to the general population and a subset that received any virtual family physician visit.

METHODS

This was a retrospective, cross-sectional study in Ontario, Canada. Patients who had received a family physician visit at 1 of 13 selected virtual walk-in clinics from April 1 to December 31, 2020, were compared to Ontario residents who had any virtual family physician visit. The main outcome was postvisit health care use.

RESULTS

Virtual walk-in patients (n=132,168) had fewer comorbidities and lower previous health care use than Ontarians with any virtual family physician visit. Virtual walk-in patients were also less likely to have a subsequent in-person visit with the same physician (309/132,168, 0.2% vs 704,759/6,412,304, 11%; standardized mean difference [SMD] 0.48), more likely to have a subsequent virtual visit (40,030/132,168, 30.3% vs 1,403,778/6,412,304, 21.9%; SMD 0.19), and twice as likely to have an emergency department visit within 30 days (11,003/132,168, 8.3% vs 262,509/6,412,304, 4.1%; SMD 0.18), an effect that persisted after adjustment and across urban/rural resident groups.

CONCLUSIONS

Compared to Ontarians attending any family physician virtual visit, virtual walk-in patients were less likely to have a subsequent in-person physician visit and were more likely to visit the emergency department. These findings will inform policy makers aiming to ensure the integration of virtual visits with longitudinal primary care.

Physician home visits in Ontario: a cross-sectional analysis of patient characteristics and postvisit use of health care services

BACKGROUND

It is unknown how much of current physician home visit volume is driven by low-complexity or low-continuity visits. Our objectives were to measure physician home visit volumes and costs in Ontario from 2005/06 to 2018/19, and to compare patient characteristics and postvisit use of health care services across home visit types.

METHODS

This was a retrospective cross-sectional study using health administrative data. We examined annual physician home visit volumes and costs from 2005/06 to 2018/19 in Ontario, and characteristics and postvisit use of health care services of residents who received at least 1 home visit from any physician in 2014/15 to 2018/19. We categorized home visits as palliative, provided to a patient who also received home care services or "other," and compared characteristics and outcomes between groups.

RESULTS

A total of 4 418 334 physician home visits were performed between 2005/06 and 2018/19. More than half (2 256 667 [51.1%]) were classified as "other" and accounted for 39.1% ($22 million) of total annual physician billing costs. From 2014/15 to 2018/19, of the 413 057 home visit patients, 240 933 (58.3%) were adults aged 65 or more, and 323 283 (78.3%) lived in large urban areas. Compared to the palliative care and home care groups, the "other" group was younger, had fewer comorbidities, and had lower rates of emergency department visits and hospital admissions in the 30 days after the visit.

INTERPRETATION

About half of physician home visits in 2014/15 to 2018/19 were to patients who were receiving neither palliative care nor home care, a group that was younger and healthier, and had low use of health care services after the visit. There is an opportunity to refine policy tools to target patients most likely to benefit from physician home visits.

Glycaemic control in transition-aged versus early adults with type 1 diabetes and the effect of a government-funded insulin pump programme

AIM

To compare glycaemic control and adverse outcomes between transition-aged and early adults with type 1 diabetes, and the impact of continuous subcutaneous insulin infusion (CSII) therapy funded through a government Assisted Devices Program.

METHODS

This retrospective cohort study using healthcare administrative databases from Ontario, Canada included adults aged 18-35 with type 1 diabetes between 1 April 2011 and 31 March 2014. Mean HbA_1c was compared between transition-aged (18-24 years) and early adults (25-35 years), overall and stratified by whether or not they received government-funded CSII therapy (CSII vs. non-CSII). Secondary outcomes included rates of hospitalizations/emergency department visits for hyperglycaemia and hypoglycaemia over a 3-year follow-up. Comparisons were adjusted for relevant covariates.

RESULTS

Among 7157 participants with type 1 diabetes, mean HbA_1c was significantly higher for transition-aged compared to early adults (71 mmol/mol [8.68%] vs. 64 mmol/mol [8.04%], p < 0.0001). This difference was smaller among CSII compared to non-CSII users (p = 0.02 for interaction between age group and CSII use). The transition-age group were more likely to experience a hyperglycaemic event compared to early adults (adjusted risk ratio, aRR: 1.56, 95% confidence interval [CI]: 1.25-1.96), which was attenuated by CSII use (aRR: 1.13, 95% CI: 0.7-1.69).

CONCLUSIONS

Transition-aged adults with type 1 diabetes had a significantly higher mean HbA_1c and risk of hyperglycaemic events compared to early adults. This difference was attenuated for CSII users, indicating that a government-funded CSII programme is associated with narrowing of the gap in glycaemic control and associated adverse outcomes for this population.

Glycemic Control and Use of High-risk Antihyperglycemic Agents Among Nursing Home Residents With Diabetes in Ontario, Canada

This cohort study examines levels of glycemic control among nursing home residents with diabetes and compares rates of intensive glycemic control with high-risk antihyperglycemic agents across levels of cognitive impairment.

Potential diabetes overtreatment and risk of adverse events among older adults in Ontario: a population-based study

AIMS/HYPOTHESIS

More than 25% of older adults (age ≥75 years) have diabetes and may be at risk of adverse events related to treatment. The aim of this study was to assess the prevalence of intensive glycaemic control in this group, potential overtreatment among older adults and the impact of overtreatment on the risk of serious events.

METHODS

We conducted a retrospective, population-based cohort study of community-dwelling older adults in Ontario using administrative data. Participants were ≥75 years of age with diagnosed diabetes treated with at least one anti-hyperglycaemic agent between 2014 and 2015. Individuals were categorised as having intensive or conservative glycaemic control (HbA_1c <53 mmol/mol [<7%] or 54-69 mmol/mol [7.1-8.5%], respectively), and as undergoing treatment with high-risk (i.e. insulin, sulfonylureas) or low-risk (other) agents. We measured the composite risk of emergency department visits, hospitalisations, or death within 30 days of reaching intensive glycaemic control with high-risk agents.

RESULTS

Among 108,620 older adults with diagnosed diabetes in Ontario, the mean (± SD) age was 80.6 (±4.5) years, 49.7% were female, and mean (± SD) diabetes duration was 13.7 (±6.3) years. Overall, 61% of individuals were treated to intensive glycaemic control and 21.6% were treated to intensive control using high-risk agents. Using inverse probability treatment weighting with propensity scores, intensive control with high-risk agents was associated with nearly 50% increased risk of the composite outcome compared with conservative glycaemic control with low-risk agents (RR 1.49, 95% CI 1.08, 2.05).

CONCLUSIONS/INTERPRETATION

Our findings underscore the need to re-evaluate glycaemic targets in older adults and to reconsider the use of anti-hyperglycaemic medications that may lead to hypoglycaemia, especially in setting of intensive glycaemic control.

Association between antihypertensive medications and risk of skin cancer in people older than 65 years: a population-based study

BACKGROUND:

The risk of skin cancer associated with antihypertensive medication use is unclear, although thiazides have been implicated in regulatory safety warnings. We aimed to assess whether use of thiazides and other antihypertensives is associated with increased rates of keratinocyte carcinoma and melanoma.

METHODS:

We conducted a population-based inception cohort study using linked administrative health data from Ontario, 1998–2017. We matched adults aged ≥ 66 years with a first prescription for an antihypertensive medication (thiazides, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, β-blockers) by age and sex to 2 unexposed adults who were prescribed a non-antihypertensive medication within 30 days of the index date. We evaluated each antihypertensive class in a separate cohort study. Our primary exposure was the cumulative dose within each class, standardized according to the World Health Organization’s Defined Daily Dose. Outcomes were time to first keratinocyte carcinoma, advanced keratinocyte carcinoma and melanoma.

RESULTS:

The inception cohorts included a total of 302 634 adults prescribed an antihypertensive medication and 605 268 unexposed adults. Increasing thiazide exposure was associated with an increased rate of incident keratinocyte carcinoma (adjusted hazard ratios [HRs] per 1 Defined Annual Dose unit 1.08, 95% confidence interval [CI] 1.03–1.14), advanced keratinocyte carcinoma (adjusted HR 1.07, 95% CI 0.93–1.23) and melanoma (adjusted HR 1.34, 95% CI 1.01–1.78). We found no consistent evidence of association between other antihypertensive classes and keratinocyte carcinoma or melanoma.

INTERPRETATION:

Higher cumulative exposure to thiazides was associated with increased rates of incident skin cancer in people aged 66 years and older. Consideration of other antihypertensive treatments in patients at high risk of skin cancer may be warranted.

Association between diabetes and haematological malignancies: a population-based study

AIMS/HYPOTHESIS

Contemporary data for the association of diabetes with haematological malignancies are lacking. We evaluated the risk of developing haematological malignancies and subsequent mortality in individuals with diabetes compared with those without diabetes.

METHODS

We conducted a population-based observational study using healthcare databases from Ontario, Canada. All Ontario residents 30 years of age or older free of cancer and diabetes between 1 January 1996 and 31 December 2015 were eligible for inclusion. Using Cox regression analyses, we explored the association between diabetes and the risk and mortality of haematological malignancies (leukaemia, lymphoma, multiple myeloma). The impact of timing on associations was evaluated with analyses stratified by time since diabetes diagnosis (<3 months, 3 months to 1 year, ≥1 year).

RESULTS

We identified 1,003,276 individuals with diabetes and age and sex matched these to 2,006,552 individuals without diabetes. Compared with individuals without diabetes, those with diabetes had a modest but significantly higher risk of a haematological malignancy (adjusted HR 1.10 [95% CI 1.08, 1.12] p < 0.0001). This association persisted across all time periods since diabetes diagnosis. Among those with haematological malignancies, diabetes was associated with a higher all-cause mortality (HR 1.36 [95% CI 1.31, 1.41] p < 0.0001) compared with no diabetes, as well as cause-specific mortality.

CONCLUSIONS/INTERPRETATION

Diabetes is associated with a higher risk of haematological malignancies and is an independent risk factor of all-cause and cause-specific mortality. Greater efforts for lifestyle modification may not only reduce diabetes burden and its complications but may also potentially lower risk of malignancy and mortality. Graphical abstract.

Levothyroxine dose and risk of atrial fibrillation: A nested case-control study

Contemporary data on the effect of levothyroxine dose on the occurrence of atrial fibrillation (AF) are lacking, particularly in the older population. Our objective was to determine the effect of cumulative levothyroxine exposure on risk of AF and ischemic stroke in older adults.

METHODS

We conducted a population-based observational study using health care databases from Ontario, Canada. We identified adults aged ≥66 years without a history of AF who filled at least 1 levothyroxine prescription between April 1, 2007, and March 31, 2016. Cases were defined as cohort members who had incident AF (emergency room visit or hospitalization) between the date of first levothyroxine prescription and December 31, 2017. Index date was date of AF. Cases were matched with up to 5 controls without AF on the same index date. Secondary outcome was ischemic stroke. Cumulative levothyroxine exposure was estimated based on total milligrams of levothyroxine dispensed in the year prior to index date. Using nested case-control approach, we compared outcomes between older adults who received high (≥0.125 mg/d), medium (0.075-0.125 mg/d), or low (0-0.075 mg/d) cumulative levothyroxine dose. We compared outcomes between current, recent past, and remote past levothyroxine use.

RESULTS

Of 183,360 older adults treated with levothyroxine (mean age 82 years; 72% women), 30,560 (16.1%) had an episode of AF. Compared to low levothyroxine exposure, high and medium exposure was associated with significantly increased risk of AF after adjustment for covariates (adjusted odds ratio [aOR] 1.29, 95% CI 1.23-1.35; aOR 1.08, 95% CI 1.04-1.11; respectively). No association was observed between levothyroxine exposure and ischemic stroke. Compared with current levothyroxine use, older adults with remote levothyroxine use had lower risks of AF (aOR 0.56, 95% CI 0.52-0.59) and ischemic stroke (aOR 0.61, 95% CI 0.56-0.67).

CONCLUSIONS

Among older persons treated with levothyroxine, levothyroxine at doses >0.075 mg/d is associated with an increased risk of AF compared to lower exposure.

Racial Differences in Home Dialysis Utilization and Outcomes in Canada

BACKGROUND AND OBJECTIVES

Data on racial disparities in home dialysis utilization and outcomes are lacking in Canada, where health care is universally available.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied patients starting maintenance dialysis between 1996 and 2012 in the Canadian Organ Replacement Register, stratified by race: white, Asian, black, Aboriginal, Indian subcontinent, and other. The association between race and treatment with home dialysis was examined using generalized linear models. Secondary outcomes assessed racial differences in all-cause mortality and technique failure using a Fine and Gray competing risk model.

RESULTS

66,600 patients initiated chronic dialysis between 1996 and 2012. Compared with whites (n=46,092), treatment with home dialysis was lower among Aboriginals (n=3866; adjusted relative risk, RR, 0.71; 95% confidence interval, CI, 0.66 to 0.76) and higher in Asians (n=4157; adjusted RR, 1.28; 95% CI, 1.22 to 1.35) and others (n=2170; adjusted RR, 1.12; 95% CI, 1.04 to 1.20) but similar in blacks (n=2143) and subcontinent Indians (n=2809). Black (adjusted hazard ratio, HR, 1.31; 95% CI, 1.16 to 1.48) and Aboriginal (adjusted HR, 1.19; 95% CI, 1.06 to 1.33) patients treated with peritoneal dialysis had a significantly higher adjusted risk of technique failure compared with whites, whereas Asians had a lower risk (adjusted HR, 0.89; 95% CI, 0.82 to 0.99). In patients on peritoneal dialysis, the risk of death was significantly lower in Asians (adjusted HR, 0.83; 95% CI, 0.75 to 0.92), blacks (adjusted HR, 0.71; 95% CI, 0.59 to 0.85), and others (adjusted HR, 0.79; 95% CI, 0.68 to 0.92) but higher in Aboriginals (adjusted HR, 1.16; 95% CI, 1.02 to 1.32) compared with whites. Among patients on home hemodialysis, no significant racial differences in patient and technique survival were observed, which may be limited by the low number of events among each subgroups.

CONCLUSIONS

With the exception of Aboriginals, all racial minority groups in Canada were as likely to be treated with home dialysis compared with whites. However, significant racial differences exist in outcomes.

Temporal Trends and Factors Associated with Home Hemodialysis Technique Survival in Canada

BACKGROUND AND OBJECTIVES

The last 15 years has seen growth in home hemodialysis (HD) utilization in Canada owing to reports of improved outcomes relative to patients on conventional in-center HD. What effect growth has had on home HD technique and patient survival during this period is not known.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

We compared the risk of home HD technique failure, mortality, and the composite outcome among three incident cohorts of patients on home HD in Canada: 1996-2002, 2003-2007, and 2008-2012. A multivariable piece-wise exponential model was used to evaluate all outcomes using inverse probability of treatment and censoring weights.

RESULTS

A total of 1869 incident patients on home HD were identified from the Canadian Organ Replacement Register. Relative to those treated between 2003 and 2007 (n=568), the risk of home HD technique failure was similar between patients treated between 1996 and 2002 (n=233; adjusted hazard ratio [AHR], 1.39; 95% confidence interval [95% CI], 0.78 to 2.46) but higher among incident patients on home HD treated between 2008 and 2012 (n=1068; AHR, 1.51; 95% CI, 1.06 to 2.15). Relative to patients treated between 2003 and 2007, adjusted mortality was similar among those treated between 2008 and 2012 (AHR, 0.83; 95% CI, 0.58 to 1.19) and those treated between 1996 and 2002 (AHR, 0.67; 95% CI, 0.38 to 1.21). The risk of the composite outcome of death and technique failure was similar across cohorts, as was the risk of receiving a kidney transplant. Increasing age, diabetes as a comorbidity, and smoking status were associated with an increased risk of death as well as the composite outcome. Medium-sized facilities had a lower risk of death, technique failure, and the composite outcome compared with larger facilities.

CONCLUSIONS

A higher risk of technique failure was seen in the most contemporary era. Further characterization of the risk factors for, and causes of technique failure is needed to develop strategies to improve patient retention on home HD.

The impact of transfer from hemodialysis on peritoneal dialysis technique survival

BACKGROUND

A significant proportion of peritoneal dialysis (PD) patients receive an initial period of hemodialysis (HD) before transitioning to PD ("PD-switch"). We sought to better understand the risks of PD technique failure (TF) and mortality for those patients compared with patients starting with PD as their first dialysis modality ("PD-first").

METHODS

Using Canadian Organ Replacement Register data, we compared the risk of PD TF between PD-first and PD-switch patients within the first year after HD initiation. In a secondary analysis, the PD-switch patients were stratified into three groups based on timing of the switch from initial HD to PD as follows: 0 - 90 days, 91 - 180 days, and 181 - 365 days. Each group was compared with PD-first patients for risk of PD TF and death.

RESULTS

Between 2001 and 2010, 9404 patients initiated PD as their first renal replacement therapy, and 3757 switched from HD to PD. After multivariable adjustment, the risk of PD TF was higher among PD-switch patients than among PD-first patients [adjusted hazard ratio (AHR): 1.37; 95% confidence interval (CI): 1.26 to 1.49], particularly within the first year after the switch from HD to PD (AHR: 1.51; 95% CI: 1.36 to 1.68). There was no association between time on HD within the first year and subsequent risk of PD TF. For all the stratified PD-switch groups, death rates were higher than those for PD-first patients.

CONCLUSIONS

Compared with patients who start renal replacement therapy with PD, those who transfer from HD to PD within the first year on dialysis experience higher rates of PD TF and death, with the highest risk being observed in the initial year after the switch to PD.

Changes in patient and technique survival over time among incident peritoneal dialysis patients in Canada

BACKGROUND AND OBJECTIVES

In the last 15 years in Canada, there have been less stringent guidelines for peritoneal dialysis (PD) adequacy, availability of novel PD solutions, and lower PD-related peritonitis rates. Effects of these changes on outcomes of incident patients treated with PD during this period are unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Risk of PD technique failure and mortality were compared among three incident cohorts of PD patients who initiated dialysis during the following periods: 1995-2000, 2001-2005, and 2006-2009. A multivariable model was used to evaluate time to PD technique failure using inverse probability of treatment and censoring weights accounting for changing survival and transplantation rates.

RESULTS

Between 1995 and 2009,13,120 incident adult PD patients were identified from the Canadian Organ Replacement Register. Compared with the 1995-2000 cohort (n=5183), the risk of PD technique failure was lower among patients between 2001 and 2005 (n=4316) but similar among incident patients between 2006 and 2009 (n=3621). Cause-specific PD technique failure revealed no difference in PD peritonitis-related technique failure over time. PD technique failure due to inadequate PD was initially higher in the 2001-2005 cohort but lower in the 2006-2009 cohort compared with the 1995-2000 cohort. Relative to incident patients between 1995 and 2000, adjusted mortality was lower among incident patients between 2001 and 2005 and 2006 and 2009.

CONCLUSIONS

Survival on PD continues to improve with only modest changes in PD technique failure. Peritonitis remains an ongoing and modifiable source of PD technique failure.

Hemodialysis vascular access modifies the association between dialysis modality and survival

Several comparisons of peritoneal dialysis (PD) and hemodialysis (HD) in incident patients with ESRD demonstrate superior survival in PD-treated patients within the first 1 to 2 years. These survival differences may be due to higher HD-related mortality as a result of high rates of incident central venous catheter (CVC) use or due to an initial survival advantage conferred by PD. We compared the survival of incident PD patients with those who initiated HD with a CVC (HD-CVC) or with a functional arteriovenous fistula or arteriovenous graft (HD-AVF/AVG). We used multivariable piece-wise exponential nonproportional and proportional hazards models to evaluate early (1 year) mortality as well as overall mortality during the period of observation using an intention-to-treat approach. We identified 40,526 incident adult dialysis patients from the Canadian Organ Replacement Register (2001 to 2008). Compared with the 7412 PD patients, 1-year mortality was similar for the 6663 HD-AVF/AVG patients but was 80% higher for the 24,437 HD-CVC patients (adjusted HR, 1.8; 95% confidence intervals [CI], 1.6 to 1.9). During the entire period of follow-up, HD-AVF/AVG patients had a lower risk for death, and HD-CVC patients had a higher risk for death compared with patients on PD. In conclusion, the use of CVCs in incident HD patients largely accounts for the early survival benefit seen with PD.

Impact of dialysis modality on survival after kidney transplant failure

BACKGROUND AND OBJECTIVES

An increasing number of patients are returning to dialysis after allograft loss (DAGL). These patients are at a higher mortality risk compared with incident ESRD patients. Among transplant-naïve patients, those treated with peritoneal dialysis (PD) enjoy an early survival advantage compared with those treated with hemodialysis (HD), but this advantage is not sustained over time. Whether a similar time-dependent survival advantage exists for PD-treated patients after allograft loss is unclear and may impact dialysis modality selection in these patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We identified 2110 adult patients who initiated dialysis after renal transplant failure between January 1991 and December 2005 from The Canadian Organ Replacement Register. Multivariable regression analysis was used to evaluate the impact of initial dialysis modality on early (2 years), late (after 2 years), and overall mortality using an intention-to-treat approach.

RESULTS

After adjustment, there was no difference in overall survival between HD- and PD-treated patients (hazard ratio((HD:PD)), 1.05; 95% confidence interval, 0.85 to 1.31), with similar results seen for both early and late survival. Superior survival was seen in more contemporary cohorts of patients returning to DAGL.

CONCLUSIONS

The use of PD compared with HD is associated with similar early and overall survival among patients initiating DAGL. Differences in both patient characteristics and predialysis management between patients returning to DAGL and transplant-naive incident dialysis patients may be responsible for the absence of an early survival advantage with the use of PD in DAGL patients.

Association between estimated glomerular filtration rate at initiation of dialysis and mortality

BACKGROUND

Recent studies have reported a trend toward earlier initiation of dialysis (i.e., at higher levels of glomerular filtration rate) and an association between early initiation and increased risk of death. We examined trends in initiation of hemodialysis within Canada and compared the risk of death between patients with early and late initiation of dialysis.

METHODS

The analytic cohort consisted of 25 910 patients at least 18 years of age who initiated hemodialysis, as identified from the Canadian Organ Replacement Register (2001-2007). We defined the initiation of dialysis as early if the estimated glomerular filtration rate was greater than 10.5 mL/min per 1.73 m². We fitted time-dependent proportional-hazards Cox models to compare the risk of death between patients with early and late initiation of dialysis.

RESULTS

Between 2001 and 2007, mean estimated glomerular filtration rate at initiation of dialysis increased from 9.3 (standard deviation [SD] 5.2) to 10.2 (SD 7.1) (p < 0.001), and the proportion of early starts rose from 28% (95% confidence interval [CI] 27%-30%) to 36% (95% CI 34%-37%). Mean glomerular filtration rate was 15.5 (SD 7.7) mL/min per 1.73 m² among those with early initiation and 7.1 (SD 2.0) mL/min per 1.73 m² among those with late initiation. The unadjusted hazard ratio (HR) for mortality with early relative to late initiation was 1.48 (95% CI 1.43-1.54). The HR decreased to 1.18 (95% CI 1.13-1.23) after adjustment for demographic characteristics, serum albumin, primary cause of end-stage renal disease, vascular access type, comorbidities, late referral and transplant status. The mortality differential between early and late initiation per 1000 patient-years narrowed after one year of follow-up, but never crossed and began widening again after 24 months of follow-up. The differences were significant at 6, 12, 30 and 36 months.

INTERPRETATION

In Canada, dialysis is being initiated at increasingly higher levels of glomerular filtration rate. A higher glomerular filtration rate at initiation of dialysis is associated with an increased risk of death that is not fully explained by differences in baseline characteristics.