Pneumonia, irregular heart beats, and obstructed blood flow to the heart are the the three main factors precipitating two out of three patients being admitted to hospital in the US for heart failure, said researchers.
The investigation is published in the 28th April issue of the Archives of Internal Medicine and is the work of researchers and clinicians based at University of California Los Angeles (UCLA), and other research centres and clinics throughout the US.
Investigators found patients had additional health problems when admitted to hospital for heart failure. These factors contributed to the decision to admit, and affected length of stay, whether they were re-admitted, and death rates, both in hospital and after discharge.
First author of the study, and UCLA’s Eliot Corday Chair in Cardiovascular Medicine and Science and director of the Ahmanson-UCLA Cardiomyopathy Center, Dr Gregg C Fonarow, said in a prepared statement that:
“Understanding the factors that can exacerbate heart failure and lead to hospitalizations — especially the ones that are avoidable — are invaluable to clinicians to help us improve management of heart failure.”
He said this was one of the largerst studies to look at the frequency and clinical impact of these factors in patients admitted to hospital with heart failure.
Around 5 million Americans have heart failure every year, a condition where the left ventricle of the heart fails to pump enough blood to other organs.
The condition leads to 3.6 million hospital admissions a year in the US.
For this study, Fonarow and colleagues used data from the Optimize-HF patient registry. Optimize-HF stands for Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients with Heart Failure, involving over 48,000 heart failure patients recruited between March 2003 and December 2004 at 259 hospitals across the US.
In addition to the hospital based data for the overall cohort, the researchers followed a subgroup of over 5,500 patients for 60 to 90 days after they left hospital to collect post-admission outcomes such as death and re-admission rates.
The mean age of the patients in the study was 73.1 years and 52 per cent were female.
The results showed that:
- 61.3 per cent of the overall patient cohort had 1 or more precipitating factors.
- The most frequent precipitating factors were: pneumonia/respiratory process (15.3 per cent of patients), ischemia (14.7 per cent), arrhythmia (13.5 per cent), and uncontrolled high blood pressure (10.7 per cent).
- Other factors included: not adhering to a special diet (5.2 per cent of patients) not taking medications (8.9 per cent), and worsening kidney function (6.8 per cent).
- In-hospital deaths were lower in the proportion of patients who did not have these factors.
- Higher in-hospital death rates were independently linked to pneumonia (60 per cent higher risk), worsening kidney function (48 per cent), and ischemia (20 per cent).
- Uncontrolled high blood pressure, on the other hand, was linked to a 26 per cent lower in-hospital death risk.
- Follow up data showed that ischemia and worsening kidney function were linked to higher risk of post-discharge mortality (52 and 46 per cent respectively).
- Uncontrolled high blood pressure was linked to 29 per cent lower post-discharge death and re-hospitalization risk.
The authors concluded:
“Precipitating factors are frequently identified in patients hospitalized for HF [heart failure] and are associated with clinical outcomes independent of other predictive variables. Increased attention to these factors, many of which are avoidable, is important in optimizing the management of HF.”
Ischemia is when the blood supply to the heart is obstructed and arrhythmia is where there is abnormal electrical activity in the heart that can cause irregular heart beat.
Fonarow said:
“The study offers important insight and points to where we can intervene early, such as making sure patients with heart failure are immunized against flu and pneumonia.”
He added that some conditions are easier to handle. For example, helping patients get back onto blood pressure medication, or follow a more sensible diet, and this may explain why the results showed lower mortality and shorter hospital stays for patients who were admitted with these factors.
Fonarow said higher risk patients might benefit from being monitored more closely when they are in hospital, from frequent follow ups after discharge, and from being taught some strategies for, and the importance of, sticking to diet and medications.
He said he and his team were planning future studies to examine how:
“Specific interventions based on these precipitating factors, such as flu vaccinations, may help this high-risk heart failure population.”
“Factors Identified as Precipitating Hospital Admissions for Heart Failure and Clinical Outcomes: Findings From OPTIMIZE-HF.”
Gregg C. Fonarow; William T. Abraham; Nancy M. Albert; Wendy Gattis Stough; Mihai Gheorghiade; Barry H. Greenberg; Christopher M. O’Connor; Karen Pieper; Jie Lena Sun; Clyde W. Yancy; James B. Young; for the OPTIMIZE-HF Investigators and Hospitals.
Arch Intern Med. 2008;168(8):847-854.
Vol. 168 No. 8, April 28, 2008
Sources: UCLA press statement, journal abstract.
Written by: Catharine Paddock, PhD