PH risk factors differ by age for people on hemodialysis: Study
Diabetes signals risk for older patients; younger ones see blood marker changes
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Risk factors for pulmonary hypertension (PH) in people receiving maintenance hemodialysis, a blood-filtering treatment used when kidney function is severely reduced, appear to change with age, according to a single-center study in China.
Diabetes was a risk factor for PH in patients 60 or older. In younger patients, PH was independently associated with a lower uric acid-to-HDL cholesterol ratio (UHR). This blood marker reflects the connections of several biological processes, such as inflammation, fat molecule metabolism, and dysfunction of cells lining blood vessels. Higher NT-proBNP, a marker of heart strain, was linked to PH in both age groups.
Overall, the findings support the need for “an age-adapted PH screening strategy” that “leads to more appropriate attention and allocates resources to those who are at a higher risk of adverse outcomes associated with PH,” the researchers wrote.
The study, “Difference in risk profiles for pulmonary hypertension between non-elderly and elderly patients undergoing maintenance hemodialysis,“ was published in BMC Nephrology.
PH occurs when the blood pressure in the pulmonary arteries becomes abnormally high. If untreated, PH can worsen over time, increasing strain on the heart and potentially leading to right heart failure.
Link to kidney function decline
The frequency of PH appears to rise as kidney function declines. It has been reported in up to 41% of people with chronic kidney disease and in as many as 60% of those with end-stage renal disease who receive hemodialysis. Yet “PH remains an under-recognized disorder frequently neglected in clinical practice,” the researchers wrote.
Diagnosing and managing PH in people on maintenance hemodialysis can be difficult because kidney and heart function are closely linked, and patients often have multiple other health conditions. Older age may further increase the risk of PH and worsen outcomes.
The research team investigated differences between age groups among patients undergoing maintenance hemodialysis, looking at the prevalence of PH as well as risk factors, death rates, and hospitalizations due to cardiovascular health reasons.
They analyzed medical records from 179 adults receiving maintenance hemodialysis at a hospital in China. Seventy-four were considered “elderly,” defined as age 60 and older. All had undergone echocardiography, an ultrasound-based heart test, and pulmonary hypertension was defined as a pulmonary artery systolic pressure higher than 35 mmHg.
PH was more common in the older group, affecting 33.8% of these patients, compared with 24.8% of those younger than 60. In both age groups, patients with PH had lower blood levels of creatinine (a standard measure of kidney function) and higher levels of NT-proBNP than people on maintenance hemodialysis without PH.
Among younger people on hemodialysis, PH was linked to a significantly lower UHR. Older patients with PH had lower hemoglobin (the protein in red blood cells that carries oxygen) and higher globulin levels than those without PH. Globulins are a group of blood proteins involved in immune responses and inflammation.
A statistical analysis confirmed that higher NT-proBNP was a risk factor for PH in both age groups. In the younger group, lower UHR was also independently associated with PH. In older patients, diabetes was identified as a risk factor.
Prediction models that combined NT-proBNP with UHR in younger patients, or NT-proBNP with diabetes in older patients, performed better than any single marker alone in identifying PH.
Patients were followed for a median of almost 33 months. During follow-up, 35 patients died, nine younger patients and 26 in the older group. Death due to any cause was significantly higher among elderly patients (35.1% vs. 8.6%).
In both age groups, people with PH had a higher combined risk of death from any cause and hospitalization due to cardiovascular reasons than those without PH. Among younger participants, PH was also associated with a higher risk of hospitalization from any cause alone.
In the older group, PH remained a strong independent predictor of cardiovascular hospitalization even after accounting for death as a variable.
“This study provides valuable clinical reference data for the early identification and intervention of PH in patients undergoing MHD [maintenance hemodialysis] based on age stratification,” the researchers concluded.
