What's the Weather Like Today? Forecasting a Chance of Shower, Snow, and… Missing Dialysis

Hemodialysis treatments are vital to preventing life-threatening complications in patients with kidney failure. Prior studies have shown that missing dialysis is associated with a higher risk of emergency department visits, hospitalizations, and mortality.^1,2 Barriers to dialysis attendance are a substantial concern to the health of patients with kidney failure. In this issue of CJASN, Remigio and colleagues³ present interesting data on the association between inclement weather conditions and the risk of missing hemodialysis in the Northeast part of the United States.

The authors included 60,135 adults treated with in-center hemodialysis at 99 Fresenius Kidney Care facilities between 2001 and 2019 for study. Using a case-crossover study design, the authors found that rainfall, sustained winds, wind gusts, snowfall, and hurricane or tropical storm events were associated with higher risk of missing hemodialysis on the day of inclement weather. This risk persisted for up to 7 days for snowfall and 2 days for sustained wind advisories, but only 1 day for rainfall. Contrary to what may have been expected, the risk of missing hemodialysis was not sustained for hurricanes and tropical storms. However, the 7-day cumulative exposure to hurricanes and tropical storms, wind advisory sustained, and wind advisory gusts was associated with a 55%, 29%, and 34% statistically significantly higher risk of missing hemodialysis treatments, respectively.³

The major strengths of this study include the novelty of the question, the large sample size, diversity of the population included, and granularity of the data that were available within the electronic health record systems, which allowed for the identification of unexcused missed treatment sessions on the dates when inclement weather occurred. Patients who missed hemodialysis sessions because of preplanned travel or hospitalization were considered to have excused absences. While prior studies have shown a higher risk of mortality in the 30 days after acute weather events, such as hurricanes, these studies have not always been able to directly incorporate details surrounding the circumstances of missed treatment sessions or have data on the frequency of dialysis treatments that were prescribed.⁴ In addition, the inclusion of a variety of different weather types beyond snow and hurricanes in this study is additive to the existing literature,^1,4 thereby extending observations surrounding the risk of missing treatments across a wider range of weather conditions, including rain. However, high-temperature conditions were not included for study, and whether extreme heat also associates with a higher risk of missing dialysis treatments was not examined.

While many studies have focused on patient-level barriers to attending dialysis treatments, Remigio and colleagues shed light on how the environment can pose additional anticipated or unanticipated challenges to dialysis attendance. Future studies of hemodialysis treatment attendance should account for patients' geographic location and frequency of their exposure to inclement weather as risk factors for missing treatments.

There are, however, a few limitations that should be highlighted. The data included in this study are derived from the Northeast, where the type and frequency of weather events may differ from that of other geographic regions. In the setting of severe inclement weather, diversion of patients to backup units for hemodialysis treatments may also be more easily facilitated in the Northeast compared with other more rural regions of the United States, where the density of hemodialysis facilities may be lower. The Northeast also has the shortest average driving distance (6 miles) to a dialysis center⁵ compared with other regions of the United States. Thus, the association between inclement weather and missed hemodialysis treatments may differ when average patient travel distances are longer and the effect size potentially larger than what was observed in this study. Data on whether there was effect modification by distance between the patient's residence and dialysis facility or rurality of patient's residence would be informative.

The average number of visits per patient per year reported in this study was 94, but assuming most patients were receiving thrice-weekly dialysis, overall dialysis attendance in this population appears modest, although the standard deviation was wide. It is not entirely clear whether there were subsets of patients who were more likely to miss their appointments across all weather types. In addition, missed dialysis treatments were not linked to clinical outcomes, including emergency department visits, hospitalizations, or deaths. These data are of interest, particularly for weather conditions that can occur frequently (e.g., rain) but were not linked to clinical outcomes in prior studies.

Providing early dialysis when weather conditions are anticipated to be severe could mitigate the incidence of missed dialysis and subsequent adverse outcomes as seen during Hurricane Sandy. A retrospective cohort study of 13,264 patients receiving in-center dialysis who lived in Hurricane Sandy–affected areas found that post-hurricane risk of emergency department visits, hospitalizations, and 30-day mortality were all higher.⁶ In the period before Sandy's landfall, regional state health officials strongly recommended that dialysis facilities offer early dialysis treatments, and the Kidney Community Emergency Response was activated to coordinate dialysis care and transportation.⁶ Thus, 59% of the study cohort received early dialysis before Sandy's landfall. A study investigating mortality after Hurricane Maria in Puerto Rico found that mortality among individuals receiving dialysis after the hurricane was not higher. The authors credited adherence to disaster preparedness guidelines and early government responses and care delivery as potential reasons for this finding.⁷ Although Remigio and colleagues attribute the lack of a persistent lagged risk of missing dialysis in the setting of hurricanes and tropical storms in this study to early in-center hemodialysis ahead of anticipated weather events, the frequency of early dialysis was not reported, and whether only certain facilities or certain patients received early dialysis (e.g., those not planning to evacuate) is unclear. Temporal trends in the association between weather and missed hemodialysis appointments were also not described, although improvements in emergency preparedness over the past two decades could potentially have attenuated the relation between inclement weather and missed dialysis treatments over time.

In other fields such as oncology, barriers to medical care during inclement weather have also been noted. For example, patients with gynecological cancer faced disruption to oncologic care and communication with their providers in Puerto Rico after Hurricanes Irma and Maria in 2017.⁸ The findings by Remigio et al. in this study highlight the critical need for more studies to investigate the relationship between weather subtypes and their association with access to treatment among patients with chronic conditions. In-center hemodialysis is particularly unique in its dependence on the availability of health care personnel and infrastructure for delivery, and the consequences of missing multiple treatments may be life-threatening because of electrolyte abnormalities, hypertensive emergencies, and pulmonary edema. Emergency stores of potassium binders and point-of-care laboratory testing equipment that could be used to help prioritize which patients need urgent treatment (when outpatient laboratory services are unavailable) may be important components of emergency responses. Patient education surrounding what to do during emergencies, staffing plans (including staff evacuation and safety), and patient communication plans when phone and internet may not be available also need to be outlined.

Current resource initiatives through the Kidney Community Emergency Response and the Department of Health and Human Services, along with state and local resource operations, provide guidance and avenues to increase patient access to hemodialysis during natural disasters. Preparation for anticipated or unanticipated disasters require dialysis facilities to consider securing backup power and alternative water sources, establishing modes of communication when phone lines may not be operational, and deployment of dialysis personnel and equipment to affected areas or diversion of patients to unaffected regions to minimize adverse clinical outcomes. This study reminds us of the clear need for robust policy, preparedness, and recognition of the association between weather and in-center hemodialysis attendance, particularly in subpopulations who face greater challenges with transportation and may have barriers to early evacuation. Ensuring equitable access to hemodialysis in the face of inclement weather will continue to require the concerted efforts and resilience of patients, dialysis facilities, providers, and communities.

Disclosures

E. Ku reports ownership interest in Edison Company; research funding from CareDX, Natera, and NIH; and other interests or relationships with Fidelity Trust and John Andrew Lang Philanthropic Fund. E. Ku is an Associate Editor for the American Journal of Kidney Diseases and a member of the American Kidney Fund Health Equity Coalition. D. Nallapothula reports ownership interest in CareDx and Invitae.

Funding

None.

Author Contributions

Conceptualization: Elaine Ku, Dhiraj Nallapothula.

Supervision: Elaine Ku.

Writing – original draft: Dhiraj Nallapothula.

Writing – review & editing: Elaine Ku, Dhiraj Nallapothula.