Almost half of hospitalisations for chronic conditions that are classified as “potentially preventable” could not have been prevented by different care or patient behaviour in the previous three months, according to an Australia-first study.

The authors say their findings raise questions about the “bluntness” of PPH measure, but also reveal opportunities to intervene to prevent some patients from being hospitalised, especially those with COPD and congestive heart failure (CHF).

The DaPPHne (Diagnosing Potentially Preventable Hospitalisations) study involved 323 patients admitted to three NSW hospitals for congestive heart failure (CHF), COPD, diabetes complications or angina pectoris between November 2014 and June 2017.

All were classified as PPH on the discharge summary.

Data was collected from patients, their GPs and hospital record and an expert panel assessed each patient’s case to determine if their hospitalisation had been preventable.

The study defined “preventable” as an unplanned admission that could have been prevented if – in the three months prior to admission – appropriate, adequate, accessible and good quality support in the community had been available and accessed, and/or appropriate individual health behaviours had occurred.

It found that 46% of the PPH were preventable, 30% were not preventable and 24% were unclassifiable, according to the findings published in BMJ Open.

The Australian Institute of Health and Welfare (AIHW), which uses PPH as a proxy measure of primary care effectiveness, found there were nearly 748,000 PPH in Australia in 2017-18.

The study authors said their findings raised questions about the “bluntness” of PPH as an indicator and revealed the extent to which PPH rates for chronic conditions overestimate the proportion of admissions that are actually preventable.

“That less than half of the PH were assessed as preventable (and nearly one third as not preventable), and the wide range of factors associated with preventability, including site and discharge diagnosis, are important factors in future consideration in the validity and use of PPH as an indicator,” they wrote

They outlined 11 predictors for preventable hospitalisation. They included the hospital site – with patients in the metropolitan hospital six times more likely to have a preventable hospitalisation than those in one of the rural hospitals – and the patients’ diagnosis, with the highest risk of preventable admission found in patients with CHF.

Living alone, regularly requiring help with daily tasks, the patient being assessed by their GP as having social issues that impacted negatively on their ability to manage their health, engaging in very little physical activity and having comorbidities, were all identified as risk factors for preventable hospitalisation.

The authors said the study suggested there were opportunities to intervene to improve clinical care and self-management in the community in the three months prior to the patients’ hospitalisation.

“The improved understanding of which chronic PPH were preventable provided by this works points to opportunities for interventions to reduce PPH among people with CHF and COPD, and the importance of the provision of social welfare and support services for patients living alone and those requiring help with daily tasks and medication management,” they wrote.

Associate Professor Isuru Ranasinghe, Conjoint Associate Professor Cardiology at Prince Charles Hospital, Brisbane and The University of Queensland, said while the study highlighted that there was still potential to reduce a significant proportion of admissions for chronic conditions.

“If you look at this study, where clearly all three experts agreed that 46% of cases were preventable, there is plenty of scope for real improvement here,” he said.

Many of the predictors of preventable hospitalisation found in the study were as expected, he said, with social isolation, living along and co-morbidities all known to increase a patient’s risk of ending up in hospital.

“it reiterates how important it is to have good primary care to look after people with multimorbidities,” he said.

The finding that patients with CHF had a high risk of preventable hospitals accorded with findings from his recent study on unplanned readmissions following hospitalisation for heart failure, which found almost one-quarter of patients were readmitted within 30 days.

While some of those readmissions were likely unavoidable due to the condition worsening, some probably could have been prevented by improvements in factors such as discharge planning, he said.

Professor Ranashinghe said PPH remained a valuable measure to give a broad, population-level overview of where improvements were needed.

“Most people are aware that not all of these [cases] are preventable,” he said.

Professor David Preen, Chair in Public Health at the University of Western Australia, said study methodology had some limitations in terms of assessing PPH, including the fact it only considered patients’ care in the three months prior to hospitalisation and that many patients with short hospital admissions were missed.

“I would argue that PPH is still very meaningful when it is used in the right context – it is more about looking at broader, population care provision over a longer period of time,” he said.

Professor Preen added that admissions for chronic conditions that were classified as ‘PPH’ were not always a bad thing, as they could enable early identification of an escalation of a patients’ condition and prompt multidisciplinary teams to intervene to prevent further complications.