Geriatric nephrology and 'sick day rules’
As people age, the kidneys undergo natural changes that affect how efficiently they function. Geriatric nephrology is the branch of medicine that focuses on diagnosing and managing kidney problems in older adults, taking into account the effects of ageing, coexisting health conditions and medication use. A key concept in this field is the application of ‘sick day rules’, which aim to protect kidney function during periods of acute illness.
Understanding kidney health in older adults
Ageing is associated with a gradual decline in kidney function, even in the absence of underlying kidney disease. Many older adults are also managing long-term conditions such as high blood pressure, diabetes or heart failure - all of which can affect the kidneys. These individuals are often prescribed medications like ACE inhibitors, diuretics or non-steroidal anti-inflammatory drugs (NSAIDs), which can increase the risk of acute kidney injury (AKI) if not carefully managed.
What are 'sick day rules'?
‘Sick day rules’ refer to guidance given to patients on certain medications to help protect kidney function during episodes of illness that may lead to dehydration. These include illnesses that cause fever, vomiting, diarrhoea or reduced fluid intake. Dehydration can significantly reduce kidney blood flow, increasing the risk of AKI, especially in older adults with already reduced kidney reserve.
During these ‘sick days’, patients are advised to temporarily stop certain medications that could further harm the kidneys. These typically include:
- ACE inhibitors (e.g. ramipril, lisinopril)
- Angiotensin receptor blockers (ARBs)
- Diuretics
- NSAIDs
- Metformin (in patients at risk of kidney impairment or dehydration)
- SGLT2 inhibitors (drugs like dapagliflozin, empagliflozin, canagliflozin, etc)
Once the patient is well again and able to maintain adequate fluid intake, they can usually restart their medications, often after consulting their healthcare provider.
The role of the geriatric nephrologist
Geriatric nephrologists play a crucial role in preventing and managing kidney-related complications in older adults. This includes:
- Monitoring kidney function regularly, particularly in patients with chronic kidney disease (CKD)
- Adjusting medications based on kidney function and age-related changes in drug metabolism
- Providing education about sick day rules and how to manage medication during intercurrent illnesses
- Coordinating care with GPs, pharmacists and other specialists to ensure safe prescribing and follow-up
They also assess other factors that may increase vulnerability, such as frailty, cognitive decline and mobility issues, and ensure that any management plan is tailored to the individual’s health goals and living situation.
Why education and early action matter
Many cases of AKI in older adults are preventable. Educating patients and carers about when to withhold certain medications, ensuring they recognise signs of dehydration, and encouraging prompt medical review can significantly reduce hospital admissions and long-term complications.
By promoting awareness of sick day rules and adopting a proactive, individualised approach, Geriatric nephrology supports older adults in maintaining kidney health and preventing unnecessary harm during common illnesses.