Hospital overcrowding: a threat to patient safety?

Hospital overcrowding causing “access block” — a lack of available inpatient beds for emergency department patients — remains a major impediment to the delivery of good health care both in Australia and overseas. It is obvious that making elderly or disabled patients wait on uncomfortable emergency trolleys in corridors, with sleep deprivation and minimal privacy, is inhumane. Previous research has shown that hospital overcrowding is actually inefficient: it is associated with increased length of hospital stay,1,2 thus potentially reducing throughput. The number of adverse events has also been shown to increase with worsening access block.3,4

Two articles in this issue of the Journal have put pressure on efforts to solve this problem. Sprivulis and colleagues5 and Richardson,6 using different methods and different populations, have shown a strong association between access block and mortality rate. Their findings now make access block a patient safety issue for which all health care workers and the community must be responsible. It is incumbent on governments and administrators to prevent overcrowding by improving management of the health care system and, where necessary, providing increased resources.

These two studies have certain methodological issues that require comment. Firstly, both studies used administrative databases. These are convenient and allow very large populations to be studied. Sprivulis et al, in their study, have also taken advantage of the linked databases in Western Australia and looked at outcomes beyond hospital admission, thus avoiding the potential bias of only studying outcomes in hospital.

Unfortunately, many data elements are not available on administrative databases. Data on physiological variables, details of treatment and past medical history, for example, were not available to more accurately adjust for risk within patient groups. It is also likely that unknown confounders may have been present, such as changing referral patterns, patient choice, and non-seasonal changes to illness patterns. Despite this, the association between periods of overcrowding and increased mortality is quite strong. Both studies have attempted to adjust for obvious confounders such as age, type of illness, seasonal effect, and so on.

What Sprivulis et al and Richardson have shown is that there is an association between overcrowding and mortality, not that overcrowding causes mortality. It is possible (but unlikely) that an influx of sick, elderly patients at high risk of death may actually cause overcrowding, thus resulting in the apparent association. Without a controlled intervention study, it is not possible to conclude that reducing overcrowding would reduce mortality. There are good reasons for assuming a causal relationship: known effects of overcrowding include delays in patient management, poor hospital processes, poor infection control, patients not being placed on the appropriate ward, and so forth. Given that it is logical that there is a causal relationship and that there is no known increased risk to patients under conditions of normal hospital bed occupancy, it is unacceptable to continue to allow hospital overcrowding to occur.

There have been many attempts to ameliorate the problem of access block across Australia7 and internationally.8 The exacerbation of access block seen in the past few years is symptomatic of much larger changes occurring within the health system. Changes to workforce, working hours, aged care, and funding, as well as fewer hospital beds, and increasing demand for seemingly limitless new treatments and procedures, have all contributed to access block. Governments have responded to these challenges by increasing resources (health care now consumes 9.6 % of Australia’s gross domestic product9), improved monitoring of performance through various indicators, and myriad initiatives to improve efficiency within hospitals as well as divert some patients away from hospitals. This effort has alleviated access block in some jurisdictions,10 but there are still major difficulties across Australia.

There are two broad strategies for managing access block resulting from hospital overcrowding — reducing hospital demand and optimising hospital bed capacity.