Trends in hospital admissions for hypoglycaemia in England: a retrospective, observational study

Summary

Background

Studies in the USA and Canada have reported increasing or stable rates of hospital admissions for hypoglycaemia. Some data from small studies are available for other countries. We aimed to gather information about long-term trends in hospital admission for hypoglycaemia and subsequent outcomes in England to help widen understanding for the global burden of hospitalisation for hypoglycaemia.

Methods

We collected data for all hospital admissions listing hypoglycaemia as primary reason of admission between Jan 1, 2005, and Dec 31, 2014, using the Hospital Episode Statistics database, which contains details of all admissions to English National Health Service (NHS) hospital trusts. We calculated trends in crude and adjusted (for age, sex, ethnic group, social deprivation, and Charlson comorbidity score) admissions for hypoglycaemia; in admissions for hypoglycaemia per total hospital admissions and per diabetes prevalence in England; and in length of stay, in-hospital mortality, and 1 month readmissions for hypoglycaemia.

Findings

79 172 people had 101 475 admissions for hypoglycaemia between 2005 and 2014, of which 72 568 (72%) occurred in people aged 60 years or older. 13 924 (18%) people had more than one admission for hypoglycaemia during the study period. The number of admissions increased steadily from 7868 in 2005, to 11 756 in 2010 (49% increase) and then remained more stable until 2014 (10 977; 39% increase from baseline, range across English regions 11–89%); the trend was similar after adjustment for risk factors, with a rate ratio of 1·53 (95% CI 1·29–1·81) for 2014 versus 2005. Admissions for hypoglycaemia per 100 000 total hospital admissions increased from 63·6 to 78·9 between 2005–06 and 2010–11 (24% increase), and then fell to 72·3 per 100 000 in 2013–14 (14% overall increase). Accounting for diabetes prevalence data, rates declined from 4·64 to 3·86 admissions per 1000 person-years with diabetes between 2010–11 and 2013–14. We were unable to compare prevalence rates with data prior to 2010, as the populations were not comparable; data were available for all individuals prior to 2010 but only for those aged 17 years or older after 2010. With some differences across regions, from 2005 to 2014, the adjusted proportion of admissions to receive same-day discharge increased by 43·8% (from 18·9 to 27·1 same-day discharges per 100 admissions); in-hospital mortality decreased by 46·3% (from 4·2 to 2·3 deaths per 100 admissions); and 1 month readmissions decreased by 63·0% (from 48·1 to 17·8 per 100 readmissions).

Interpretation

Over 10 years, hospital admissions in England for hypoglycaemia increased by 39% in absolute terms and by 14% considering the general increase in hospitalisation; however, accounting for diabetes prevalence, there was a reduction of admission rates. Hospital length of stay, mortality, and 1 month readmissions decreased progressively and consistently during the study period. Given the continuous rise of diabetes prevalence, ageing population, and costs associated with hypoglycaemia, individual and national initiatives should be implemented to reduce the burden of hospital admissions for hypoglycaemia.

Funding

None.

Introduction

Intensive glucose control reduces long-term risk of microvascular and, to some extent, macrovascular complications of diabetes in randomised controlled trials.¹ However, striving for intensive control could result in higher rates of hypoglycaemia.² Because hypoglycaemia is associated with a deterioration in quality of life and possibly a higher risk of vascular events and mortality,3, 4, 5, 6, 7, 8, 9 clinicians often face a trade-off between the benefits of intensive glucose lowering and the drawbacks of hypoglycaemia.

Most hypoglycaemic episodes are generally mild and can be self–treated by patients. Severe episodes that require assistance are less common (one or two episodes per year in insulin-treated patients), but represent a great economic burden on health-care systems.10, 11 Some of these episodes require paramedic support, attendance at accident and emergency departments, or hospital admission. Precise estimates of the proportion of patients requiring these different services are not available in England, mainly because of a lack of nationally integrated electronic health record systems. Although hospital admissions for hypoglycaemia represent a small proportion of emergency department visits, they have substantial resource implications.¹¹ The mean cost per admission for hypoglycaemia in England has been estimated to be slightly in excess of £1000, with a total direct cost of severe hypoglycaemic episodes of around £13 million every year in the UK.12, 13

Research in context

Evidence before this study

We searched PubMed for papers published in English between Jan 1, 1990, and Jan 20, 2016, using the terms “hospital”, “emergency”, and “hypoglyc(a)emia”. No specific inclusion or exclusion criteria were applied. Temporal trends in emergency department visits or hospital admissions for hypoglycaemia were reported in three studies published in USA and one in Canada. Overall, these studies suggested no trends, a peak followed by a decline or a continuous decline over time of emergency department visits or hospital admissions for hypoglycaemia. Although some studies have assessed emergency department visits or admissions for hypoglycaemia at regional or local level, no data at national level for England were available.

Added value of this study

To our knowledge, this is the first report of trends in admissions for hypoglycaemia at a national level. We investigated all hospital admissions in England showing a constant increase until 2010 and a stabilisation thereafter. Both our findings and previous studies, found a decline in admissions when accounting for diabetes prevalence and, although differently defined, a reduction of 1 month readmissions and mortality. Moreover, we also found a steadily reduction in length of hospital stay. Taken together, the reduced risk of readmission and death and the shorter hospital stay would suggest an improved outpatient and inpatient care. Along with North American data, our results can contribute to a better understanding of the global burden of hospitalisation for hypoglycaemia.

Implications of all the available evidence

Given the rise in diabetes prevalence, population age, and the risk of potential overtreatment in older people, our findings indicate that further measures will be needed to stabilise or reduce emergency department visits and hospital admissions for hypoglycaemia in the future. More detailed data could inform the best approach to reduce hospital admissions and identify where resources should be allocated.

Older age, multimorbidity, and insulin therapy are well-recognised and inter-related risk factors for hypoglycaemia.¹⁴ Given the rise in diabetes prevalence and an ageing population,15, 16 the number of admissions to hospital due to hypoglycaemia has possibly increased in recent years. This rise has recently been confirmed in a nationally representative sample of people from the USA,¹⁷ but very few data are available for other countries and little is known on a global scale. Detailed analysis of contemporary trends for England can therefore contribute to understand the global burden of hospitalisation for hypoglycaemia. In this study, we aimed to characterise the 10 year trends, from 2005 to 2014, in hospital admissions for hypoglycaemia and in associated hospital stay lengths, mortality, and readmissions using the Hospital Episode Statistics (HES) database.