The implications of high bed occupancy rates on hospital behaviour and quality of care in England

The English National Health Service has experienced significant increases in the percentage of hospital beds that are occupied at any point in time, from an average of 84.5% in 2006/07 to 91.4% in 2016/17. Moreover, it is not uncommon for some hospitals to reach 100% bed utilisation at certain times of the day. This is the consequence of an evolving mismatch between supply and demand side factors, including a consistent decrease in hospital bed stock at a time of significant rises in the number of hospital admissions. Across OECD countries, only hospitals in Canada, Ireland and Israel are experiencing higher average bed occupancy rates.

Clinical leadership has expressed concern about rises in bed occupancy rates and how they might affect the ability of hospital teams to deliver high quality care. Specifically, these relate to an increased likelihood of adverse events, challenges in securing the resources needed to diagnose and treat patients through for instance, lower staff to patient ratios, and problems with planning for the discharge of larger numbers of patients. Despite the salience of the issue to resource-stretched hospitals, few studies have examined the implications of high bed occupancy rates on hospital behaviour and quality of care.

This is the first study to assess daily changes in bed occupancy rates and their relationship with risk-adjusted, patient discharge rates and their subsequent risk-adjusted, 30-day readmission rate, from April 2014 to February 2016. English Hospital Episode Statistics data was used to identify all patients treated in English hospitals across the observation period, with the daily hospital-level bed occupancy rate calculated as the ratio of registered inpatients at midnight and the recorded stock of hospital beds. We constructed panel data models for each hospital and day across the observation period, using ordinary least squares estimators with hospital fixed effects to relate changes in daily bed occupancy rates to the two outcome variables. Sensitivity analysis was conducted for a range of selected patient subgroups, including patients of different ages, with different comorbidities and from varying socioeconomic backgrounds.

We find that an increase in bed occupancy rate by 1% was associated with a 0.49% (p<0.001) rise in the discharge rate, and a 0.011% (p<0.001) increase in the 30-day readmission rate for discharged patients. These associations became more pronounced once bed occupancy reaches the highest tertile of the bed occupancy distribution, around 95%, with each extra 1% rise in bed occupancy associated with a 0.04% (p<0.001) rise in the readmission rate. Older patients (e.g. patients aged 81 to 90 years) and those with a greater number of comorbidities (e.g. 5 comorbidities) were less likely to be discharged at times of high bed occupancy, but if they were discharged, they had an increased risk of readmission.

In this study, we find that when bed occupancy rates are high, hospitals discharge a greater proportion of their patients. However, increased bed occupancy was not associated with a substantial increase in 30-day readmission rates. It may be that hospitals are successfully prioritising early discharge among the least vulnerable patients.