Chronic diseases in disasters: insulin, dialysis, oxygen

Three days after a major storm, an improvised shelter in a school receives dozens of families. The health team, assembled in a hurry, expected to treat mostly cuts, fractures and diarrhea. On the first morning, the line is different. A man on hemodialysis three times a week has missed two sessions and is short of breath with swollen legs. A teenager with type 1 diabetes left the insulin in the refrigerator at home, which ended up underwater. An elderly woman who uses oxygen at home arrived with the concentrator, but there is no stable electricity. An elderly man lost his blood pressure and heart medications. The scene is fictional and was written for teaching. This text uses that picture as a setting for clinical reasoning: who cannot go without treatment after a disaster, how to prioritize, what to ask and which simple measures prevent deaths that could be prevented.

NEXO is a daily medical diagnosis game: one clinical case a day, up to six progressive clues, and ICD-10 proximity feedback across five levels.

This text is not a disaster response protocol. Shelter organization, medication logistics and emergency dialysis follow their own plans and local decisions. The interest here is the reasoning: how to look at a line of people with chronic diseases and recognize who is a few hours away from a serious complication. If you play the case of the day on NEXO, you will recognize the move: sometimes the most important clue is the treatment the patient did not receive.

Key points

• After a disaster, much of the demand comes from people with chronic diseases who have lost access to medications, devices and services.
• Some interruptions can kill quickly: dialysis, insulin in type 1 diabetes, oxygen, transplant medications and anticoagulation for a mechanical valve.
• Stopping certain medications suddenly is also dangerous, and the rule is to avoid abrupt discontinuation.
• Heart attacks and strokes can be two to three times more frequent after emergencies.
• Lists of patients with critical needs, medication reserves and individual plans save lives before the disaster.

Why chronic diseases matter in a disaster

The usual image of a disaster is one of trauma and infections. The World Health Organization notes that noncommunicable chronic diseases, such as cardiovascular disease, diabetes, cancer and chronic lung disease, are already the leading causes of death and disability worldwide, and that their importance in humanitarian emergencies is not yet fully recognized (World Health Organization, 2016). The document also cites dialysis-dependent kidney failure and epilepsy among the conditions that matter in emergencies.

What the scene teaches

In the opening scene, none of the four patients has an injury caused directly by the storm. All are at risk because treatment was interrupted. The man on dialysis may have too much potassium in the blood and too much fluid in the body. The teenager may go into ketoacidosis. The elderly woman may be short of oxygen. The elderly man may have a cardiovascular event. The post on signs, symptoms and history shows how the history of treatment is a clue as important as the exam.

What the reviews show

Ryan and colleagues reviewed studies on the impact of cyclones, storms and floods on people with chronic diseases (Ryan and colleagues, 2015). The authors concluded that these disasters interrupt treatment and care, which increases the risk of worsening disease and even death. The interruption can come from damaged roads, reduced health services, power outages and evacuations. For people with chronic lung disease, the disaster increases the risk of an acute attack, and for people with cancer, cardiovascular disease and diabetes, it increases the risk of worsening that can lead to death.

How a disaster worsens chronic disease

The World Health Organization describes four pathways through which an emergency compromises the health of people with chronic disease (World Health Organization, 2016). The first is physical injuries, which can trigger cardiovascular events, worsen respiratory diseases and destabilize diabetes. The second is forced displacement, with loss of medicines, prescriptions, devices and access to services. The third is the worsening of living conditions, with loss of shelter, lack of water and food and physical and psychological stress. The fourth is the interruption of care, through the destruction of services, lack of supplies and absent professionals.

The heart under stress

The World Health Organization reports that, after emergencies, heart attacks and strokes can become two to three times more frequent than before (World Health Organization, 2016). Hayman and colleagues reviewed studies on cardiovascular disease after humanitarian emergencies and concluded that, in certain contexts, these emergencies are associated with an increase in cardiovascular illness and death that can persist for years (Hayman and colleagues, 2015). The authors found varied effects after natural disasters, including more acute coronary syndromes, more decompensated heart failure and more sudden death.

Older adults and people with multiple diseases

The World Health Organization notes that older adults are particularly vulnerable and that chronic diseases require continuous care, often for a lifetime, with medicines or devices (World Health Organization, 2016). The document adds that these diseases reduce a person's ability to cope with the emergency and require coordination between different services. An older adult with multiple diseases, who depends on someone to fetch medicines, may be the most fragile patient in the shelter, even without an acute complaint.

Those who cannot wait

The World Health Organization recommends that, in the first thirty to ninety days after an emergency, and especially in the first week, care for chronic diseases focus on conditions that threaten life or cause severe symptoms (World Health Organization, 2016). This includes people who have or are at high risk of an acute complication, such as a heart attack, people with intense physical distress, such as shortness of breath from heart failure, and people who may die or suffer greatly if treatment is interrupted, such as people on dialysis.

The critical-needs subgroup

The World Health Organization recommends actively identifying the subgroup of patients for whom interruption of treatment can be fatal or critical (World Health Organization, 2016). The document cites people on dialysis, with type 1 diabetes, transplant recipients, people with a mechanical heart valve using anticoagulants and people using controlled medicines whose sudden withdrawal can be dangerous. The document also recommends avoiding sudden suspension of treatment and prioritizing the needs of these patients. In the opening scene, three of the four patients belong to this subgroup.

Asking instead of waiting for the complaint

Many of these people do not arrive asking for help. The man on dialysis may think the shortness of breath is tiredness, and the teenager may not say she is out of insulin. A simple question at the shelter entrance, about what medicines, devices and treatments the person used before the disaster, can find those at risk before the complication. The post on pretest probability helps to think about how a treatment history changes each person's risk.

Dialysis: when power and water run out

The World Health Organization notes that interruption of power or safe water can have serious consequences, especially for people with end-stage kidney disease who depend on dialysis (World Health Organization, 2016). Hemodialysis depends on electricity, treated water, staff and transport. When one of these is missing, the session does not happen.

What the studies show

Abir and colleagues studied hemodialysis centers after a major power outage caused by storms and found that about three in ten centers had operations affected (Abir and colleagues, 2013). Among the centers that lost power, some sent patients to other centers and some rescheduled sessions for another shift or another day. Only about a third of the centers had their own generator. Remigio and colleagues analyzed records of patients on hemodialysis and found more missed sessions on days of heavy rain, storms, snow and wind (Remigio and colleagues, 2023). The authors note that missing sessions can cause complications and increase illness and death. Anderson and colleagues interviewed patients on hemodialysis after a major hurricane and found that almost half missed at least one session (Anderson and colleagues, 2009). Those who missed three sessions or more had about twice the chance of hospitalization. Missing sessions was more common among those who lived alone, did not know the center's emergency plan, did not leave before the hurricane arrived or were taken to a shelter.

Reasoning with the patient on dialysis

For the clinician at the shelter, the central question is how many sessions were missed and when the last one was. A patient who missed sessions can build up potassium, fluid and acids in the blood. Shortness of breath, swelling, muscle weakness, palpitations and confusion are warning signs. Excess potassium can cause serious arrhythmias without warning. In the opening scene, the man with shortness of breath and swollen legs needs immediate assessment and referral to a center that provides dialysis, not an appointment scheduled for the next day. The World Health Organization lists international kidney disaster support groups among possible partners (World Health Organization, 2016).

Insulin: type 1 diabetes does not tolerate interruption

The World Health Organization includes people with type 1 diabetes among those for whom interruption of treatment can be fatal (World Health Organization, 2016). Without insulin, the body starts using fat as fuel and produces acids, which can lead to ketoacidosis in a short time. In the opening scene, the teenager who lost her insulin is a priority, even if she seems fine in line. Fonseca and colleagues compared tests of adults with diabetes before and after a major hurricane and found increased blood pressure in the three health systems studied and increased cholesterol in two of them (Fonseca and colleagues, 2009). The authors concluded that the disaster harmed diabetes control and increased inequalities that already existed.

The refrigerator that does not exist

A frequent question in disasters is what to do with insulin when there is no refrigerator. Kaufmann and colleagues measured the temperature in a refugee camp in a hot climate, where it ranged between twenty-five and thirty-seven degrees, and reproduced these conditions in the laboratory (Kaufmann and colleagues, 2021). The insulins tested remained stable and biologically active during the four weeks of use. Richter and colleagues reviewed studies on the stability of human insulin and concluded that, in difficult conditions, closed vials of regular and intermediate-acting insulin can be stored at up to twenty-five degrees for up to six months and at up to thirty-seven degrees for up to two months without important loss of potency (Richter and colleagues, 2023).

Simple cooling measures

Richter and colleagues also concluded that the temperature at which insulin is stored can be reduced with simple devices, such as clay pots (Richter and colleagues, 2023). The authors note that clinical evidence on insulin stored outside the refrigerator is still limited and that data are lacking on mixed insulins, insulin pumps and cold climates. For reasoning, the message is that the lack of a refrigerator should not, by itself, interrupt insulin. Insulin should be kept away from direct sunlight and extreme heat, and local guidance should be followed.

Oxygen: the device that depends on the power outlet

Many people with chronic lung disease use oxygen concentrators at home, which depend on electricity. Sato and colleagues sent questionnaires to patients using home oxygen in a region near an area hit by a major earthquake, with power outages (Sato and colleagues, 2013). Most received oxygen cylinders before their own ran out, but some patients stopped or reduced their oxygen on their own. The authors found that stopping was associated with knowledge about the therapy and anxiety about the supply.

Reasoning when someone uses oxygen

In the opening scene, the woman arrived with the concentrator, but without stable power it does not work. The central questions are how much oxygen she uses, how long she can go without it, whether the battery is charged and where there are cylinders or a generator. The World Health Organization recommends creating lists of patients with critical needs, such as those who use ventilators at home (World Health Organization, 2016). Ryan and colleagues note that power outages are one of the causes of interrupted care after disasters (Ryan and colleagues, 2015).

The other medicines that cannot stop

The World Health Organization includes transplant recipients and people with a mechanical heart valve on anticoagulants in the group with critical needs (World Health Organization, 2016). Without the medicines that prevent rejection, a transplanted organ can be lost. Without anticoagulation, a mechanical valve can form clots that cause a stroke or valve failure. The document also cites controlled medicines whose sudden discontinuation can be dangerous.

Hypertension, heart and epilepsy

The World Health Organization notes that the patients with chronic disease seen most often in emergencies are those who had an already identified and treated disease or risk factor, such as high blood pressure (World Health Organization, 2016). These patients are not at immediate risk, but they need access to medicines and tests to continue treatment. The document also cites epilepsy among the important conditions, and missing the medicine can trigger seizures. In the opening scene, the man who lost his heart medicines needs a new prescription and attention to warning signs.

Priorities in the shelter: a table for care

The table below summarizes, in a teaching format, common situations in the shelter and what usually weighs on the decision. It simplifies a complex topic and does not replace current guidelines, local plans or clinical judgment.

Situation	What weighs on the decision	Frequent approach
Dialysis with missed sessions	Accumulated potassium and fluid	Immediate assessment and referral for dialysis
Type 1 diabetes without insulin	Risk of ketoacidosis	Replace insulin without delay, even without a refrigerator
Home oxygen without power	Lack of oxygen	Cylinders, battery or generator and assessment of breathing
Transplant or mechanical valve	Rejection or clot	Maintain medicines and anticoagulation
Controlled medicines or epilepsy medicines	Withdrawal or seizures	Avoid sudden discontinuation
High blood pressure or stable heart disease	Increased cardiovascular risk	Replace medicines and explain warning signs

After the first week

The World Health Organization recommends that, in the recovery phase or in prolonged emergencies, such as long-term settlements, care for chronic diseases expand to less acute conditions, continuous follow-up and palliative care (World Health Organization, 2016). The document suggests using the organization's own package of essential interventions for chronic diseases, with protocols, medicines and equipment for the most common diseases. It also recommends ensuring access to basic tests, medicines for pain and care for symptoms of advanced disease.

Cancer

The World Health Organization treats cancer patients as a separate group, because many treatments require a hospital, intravenous administration and several consecutive days (World Health Organization, 2016). The document notes that the capacity to treat cancer may already be limited before the emergency and recommends addressing the ethical dilemmas about scarce resources and priorities. Clinical reasoning here includes pain, symptoms and palliative care, and not only continuity of treatment.

Preparation before the disaster

The World Health Organization recommends that emergency plans include protection of important health services, stockpiles of medicines and equipment, specific plans for hospitals and dialysis centers, individual plans with a medicine reserve and instructions for emergencies, and lists of patients with critical needs, such as those who use ventilators at home, undergo dialysis or have type 1 diabetes (World Health Organization, 2016). For the primary care clinician, this means asking today, before the disaster, whether the patient has a medicine reserve and a prescription put away. Arrieta and colleagues interviewed professionals and patients after a major hurricane and found that the most cited barrier to chronic disease care was maintaining continuity of medicines (Arrieta and colleagues, 2009). Inaccessible medical records and little patient knowledge about their own treatment made the problem worse. Among the solutions, participants cited education before the disaster, personal health records and the possibility of renewing prescriptions in advance.

The biases that get in the way of care

Chronic disease care in a disaster rarely fails for lack of knowledge. It usually fails because of predictable habits and biases:

1. Looking only for injuries and infections and forgetting those who lost their treatment.
2. Waiting for the patient to complain instead of asking about medicines and devices.
3. Treating the lack of a refrigerator as a reason to suspend insulin.
4. Leaving for later the dialysis patient who is still walking.
5. Suspending all at once medicines that cannot be interrupted.

Croskerry describes anchoring and premature closure among the most frequent cognitive errors in diagnosis (Croskerry, 2003). The post about the diagnostic pause shows how a short moment of checking helps to notice what was left out. The post about heuristics in clinical reasoning helps to recognize when an expectation about the type of patient changes what the professional looks for.

What to ask at the shelter entrance

Some questions organize the triage of chronic diseases:

• What medicines was the person using before the disaster and when did they take the last dose?
• Do they undergo dialysis? When was the last session?
• Do they use insulin? Do they have insulin with them?
• Do they use oxygen, a ventilator or another device that depends on power?
• Are they a transplant recipient, do they use an anticoagulant or controlled medicines?
• Do they have shortness of breath, chest pain, swelling, confusion or vomiting?

Back to the scene

In the opening scene, the team organizes the reasoning for the queue and asks the questions above. The man on dialysis is assessed first and referred urgently to a center that has power and water. The teenager receives insulin the same day, with guidance on how to store it away from the heat. The woman receives a cylinder or access to a generator-powered outlet while the team assesses her breathing. The man receives a new prescription and guidance on warning signs. The team starts a list of the shelter's patients with critical needs. The reasoning starts with the question about interrupted treatment, and not with the most visible complaint.

How NEXO helps train this reasoning

In NEXO, the case of the day is fictional, with a real clinical presentation and up to six progressive clues. You propose a diagnosis by searching for the ICD-10 code and receive proximity feedback at five levels, which shows whether the guess stayed at the exact code, the same category, the same group, the same chapter or a different chapter. This format connects with the theme of this text: the decisive clue may lie in what the patient stopped doing.

To use the case of the day as training, try three habits. Before each guess, ask what treatment the patient was using and whether it was interrupted. When a vague complaint appears, such as fatigue or swelling, ask which chronic disease could be decompensating. After the result, note which clue would have anticipated the diagnosis.

Three exercises with cases

Look for the interrupted treatment. In each case, ask which medicine or device, if it were missing, would change the picture.

Sort by urgency. Reread a case imagining that several patients arrive together and decide who cannot wait.

Think about preparation. Facing a chronic patient, list what they would need to have stored to handle an emergency.

The post about learning based on clinical cases shows how cases help fix patterns that rarely appear in daily practice.

The limits on using the game are described on the NEXO economy page. If you research the teaching of clinical reasoning, the page for researchers explains how to get in touch. Professionals who write or review cases find information on curation and on creators, and institutions can learn about the proposal on the partnerships page.

Frequently asked questions

Why do chronic diseases matter so much in disasters?

Because a disaster interrupts medicines, devices and services, and many deaths after a disaster come from the worsening of diseases that already existed.

Who has priority?

People on dialysis, with type 1 diabetes, transplant recipients, with a mechanical valve on anticoagulants, on oxygen and on medicines that cannot be stopped suddenly.

Does insulin spoil without a refrigerator?

Studies show that human insulin keeps its potency for weeks to months at tropical heat temperatures, and that clay pots and other simple devices help lower the temperature.

What should be done for the patient who missed dialysis sessions?

Assess for signs of excess potassium and fluid and refer urgently to a center that can perform dialysis.

Do heart attacks and strokes increase after a disaster?

Yes. The World Health Organization reports that they can become two to three times more frequent than before the emergency.

What can the patient do before a disaster?

Keep a supply of medicines, a stored prescription, written instructions for emergencies and know where to get dialysis, oxygen or insulin.

Final checklist

• I asked each person about medicines, devices and previous treatments.
• I identified who is on dialysis, uses insulin, oxygen or anticoagulants, or is a transplant recipient.
• I avoided the sudden stopping of critical medicines.
• I urgently referred those who missed dialysis sessions.
• I kept the insulin, even without a refrigerator, with storage guidance.
• I started a list of patients with critical needs.

Want to practice reasoning with progressive clues? Play the case of the day.

References

1. Abir M, Jan S, Jubelt L, et al. The impact of a large-scale power outage on hemodialysis center operations. Prehosp Disaster Med. 2013. PMID 23965738.
2. Anderson AH, Cohen AJ, Kutner NG, et al. Missed dialysis sessions and hospitalization in hemodialysis patients after Hurricane Katrina. Kidney Int. 2009. PMID 19212421.
3. Arrieta MI, Foreman RD, Crook ED, Icenogle ML. Providing continuity of care for chronic diseases in the aftermath of Katrina: from field experience to policy recommendations. Disaster Med Public Health Prep. 2009. PMID 19865042.
4. Croskerry P. The importance of cognitive errors in diagnosis and strategies to minimize them. Acad Med. 2003. PMID 12915363.
5. Fonseca VA, Smith H, Kuhadiya N, et al. Impact of a natural disaster on diabetes: exacerbation of disparities and long-term consequences. Diabetes Care. 2009. PMID 19542210.
6. Hayman KG, Sharma D, Wardlow RD, Singh S. Burden of cardiovascular morbidity and mortality following humanitarian emergencies: a systematic literature review. Prehosp Disaster Med. 2015. PMID 25499440.
7. Kaufmann B, Boulle P, Berthou F, et al. Heat-stability study of various insulin types in tropical temperature conditions: new insights towards improving diabetes care. PLoS One. 2021. PMID 33534816.
8. World Health Organization. Noncommunicable diseases in emergencies. 2016. Document.
9. Remigio RV, Song H, Raimann JG, et al. Inclement weather and risk of missing scheduled hemodialysis appointments among patients with kidney failure. Clin J Am Soc Nephrol. 2023. PMID 37071662.
10. Richter B, Bongaerts B, Metzendorf MI. Thermal stability and storage of human insulin. Cochrane Database Syst Rev. 2023. PMID 37930742.
11. Ryan B, Franklin RC, Burkle FM, et al. Identifying and describing the impact of cyclone, storm and flood related disasters on treatment management, care and exacerbations of non-communicable diseases and the implications for public health. PLoS Curr. 2015. PMID 26468423.
12. Sato K, Morita R, Tsukamoto K, et al. Questionnaire survey on the continuity of home oxygen therapy after a disaster with power outages. Respir Investig. 2013. PMID 23561253.