Temporal trends in healthcare resource utilization and costs following acute myocardial infarction

Survivors of acute myocardial infarction (AMI) continue to be at greater risk and utilize more healthcare resources, resulting in increased economic burden [1‐3]. Moreover, expenditure throughout the first year following an AMI seems to be exceptionally high, estimated between $22,000–$87,000 (European countries and the United States) [3‐6]. Most aspects of AMI management have experienced dramatic changes throughout recent years, including patient characteristics, presentation, invasive procedures, medical therapy, and outcomes which overall have improved significantly [1, 7]. However, data dealing with healthcare resource utilization and expenditure are sparse and inconsistent [8, 9]. The aim of the current study was to evaluate the temporal trends in healthcare resource utilization and costs following AMI.

The current study investigated temporal trends in healthcare resource utilization throughout more than a decade (2003–2015) among post-AMI patients. Main findings include: throughout the investigated period utilization of most health-care resources, particularly the length of hospital stay and primary clinic visits have decreased. However, a major increase in ED visits was observed. The unadjusted healthcare expenditure has decreased throughout the study period. When this analysis is adjusted for potential confounders no statistically significant change in total cost was observed.

It has been widely described that AMI survivors are prone to increased morbidity (compared to matched general population), healthcare services utilization and economic burden which seem to be exceptionally high throughout the first year after the AMI followed by some subsequent decline [2‐5, 16]. We found a significant attenuation in the length of hospitalizations and ambulatory services utilization throughout the last decade yet an increase in the rate of ED visits and no change in total cost. This finding is consistent with the findings of Chen et al. [17] that showed a decrease in hospitalization of AMI patients (for heart failure) in Medicare beneficiaries 1998–2010 and with those of Chaudhry et al. [18] who reported a decline in the rate of recurrent AMI hospitalization between 1999 and 2000. Likosky et al. [9],who investigated readmission rate within the first year following AMI, found no difference throughout 1998–2008. Importantly, our analysis includes all hospitalizations rather than those for a particular cause, while previous reports showed that about 30% of readmissions are for reasons unrelated to the original condition [19]. In partial consistency with our findings, a recent report from the US found significant differences across the country and between different services, in ambulatory and outpatient resource utilization and expenditure following hospital discharge with an AMI (31–180 days) between 1999 and 2014 [20].

The current study was not designed to determine the causes for the observed time dependent changes. However, several reasons can be suggested to explain the decline in hospitalizations and primary medicine services utilization. First and foremost, introduction of evidence based treatments in the acute phase management incorporated into AMI guidelines, improvements in the timeliness, and in particularly the use of invasive revascularization treatments as also observed in the current study [21, 22]. Furthermore, significant improvements have been reported in secondary prevention treatments and post discharge management including control of risk factors, the use of guideline recommended medications and rehabilitation [18, 23]. Improved post-discharge adherence with guideline recommended therapies, as observed in the current study, is also an important factor which has previously been reported to be associated with reduced healthcare resources utilization [14]. It should be mentioned that individual long-term healthcare resource utilization tends to decrease after the first year post AMI [16]. However, this individual decline does not seem to be a prominent explanation for the observed trend in the current study, since an adjustment for the time from the index AMI (the second level models) was performed.

A trend of increase in ED visits was observed throughout the years, consistent with previous reports [20]. This disparity in the trends of ED utilization and the other resources could possibly be attributed to increased awareness and caution by the AMI survivors and their healthcare providers to complaints that could be related to an acute cardiac condition. Alternatively insufficient availability of out-of-hospital services could all also cause increased frequency of ED visits [24]. Furthermore, the exceptionally greater increase in the ED visits overtime should be a focus of further investigation and intervention; for example, dedicated high quality out of hospital services with utilization of high sensitivity troponin point-of-care essays or the establishment of chest pain unit for such patient. In addition, a trend of increased age, increased prevalence of cardiovascular risk factors and other comorbidity were reported among AMI patients. The latter trends could counter-balance a trend of reduction and support a trend of increase in healthcare resources (e.g. ED visits) utilization [25, 26].

Total annual healthcare expenditure found in this study is lower than that reported in other studies [9‐12]. This disagreement is probably due to differences in healthcare and insurance systems and the methodology for estimating healthcare expenditure. The unadjusted (the first level model) and the adjusted to time from AMI (the second level model), total cost has shown a significant trend of decrease throughout the evaluated decade. However, following adjustment to multiple potential confounders in a multivariate model (the third level model) we did not find statistically significant differences in overall healthcare expenditure throughout the investigated time period. The latter findings probably mean that the unadjusted decrease in costs is explained by the changes in patient characteristics, administered treatments (e.g. increase in interventional therapy) and improvement in adherence with medical therapy. A previous report, [9] found an increase of 16.5% in the healthcare expenditure per AMI patient between the years 1998–2008 in the US. Interestingly, the authors found that expenditures for skilled nursing facilities, hospice, home health agency, durable medical equipment, and outpatient care nearly doubled during the period of 31–365 days after admission. The differences can stem from different study periods, adjustment to confounders as well as differences in healthcare systems. A recent report that evaluated expenditure on Medicare beneficiaries 180 days following AMI in four time periods 1999–2000, 2004, 2008 and 2013–2014) found that expenditure increased 13.9% from 1999 to 2000, and 2013,-2014, but declined 0.5% between 2008 and 2013–2014 [20]. It should however be mentioned that excluding patients that died throughout the first year might have resulted in underestimation of costs since treating these patients is usually associated with increased expenditure [16]. This possibly had an impact over the temporal trend of costs, especially when considering the trend of improvement in short term survival observed during the study period [7].

Our findings should be discussed considering several important characteristics of the Israeli health care system. Israel has a national health insurance financed predominantly via progressive taxation and includes four competing, non-profit health plans (HPs) which provide a broad package of services determined by the government [27, 28]. The HPs provide care in the community and purchase hospital services for their members. Nevertheless, approximately 40% of health care expenditure is financed privately. Access to primary care physicians and community-based specialists is good overall (travel and waiting times), although in some areas and populations (e.g. Israeli Arabs) it could be insufficient resulting in excessive use of hospital services. The occupancy rates of Israeli hospitals is one of the highest among the Organization for Economic Co-operation and Development (OECD) countries (greater than 90%) while the length of stay is one of the shortest (around 4 days) [27, 28]. Furthermore, hospital pricing system is considered outdated and limits their reimbursement while pricing of novel procedures and technologies and rising.

The current study has several limitations. First, the study is retrospective and based mostly on administrative data (e.g. ICD-9-CM codes) hence prone for bias resulting from such a design such as recording bias. Furthermore, such a design also does not enable identification of the causes for the observed trends. Second, patients from only one hospital with unique characteristics, population mix and from a unique region in Israel were evaluated hence generalizability is limited. Third, differentiation of cardiovascular from non-cardiovascular related healthcare services utilization was not performed. Fourth, out of pocket expenses were not evaluated thus true costs are probably higher. Fifth, it is possible that unaccounted changes, not directly related to the AMI, in patients’ health throughout the individual follow-up might have led to changes in health care utilization.

The current study investigated temporal trends in healthcare resource utilization and costs in post-AMI patients throughout 2003–2015. The study shows a significant decrease in the length of the in-hospital stay and ambulatory services utilization with an increase in ED visits. Total costs (unadjusted or adjusted for the time following AMI), have declined. However, following adjustment for a variety of potential confounders no significant trend was found. Further and more comprehensive studies evaluating such trends, mechanisms and causes behind the observed findings, as well as the association between hospital services utilization and ambulatory utilization of healthcare services and costs in general and in subgroups of interest, are warranted, in order to improve resource allocation, patient outcomes and maximize cost-effectiveness in the long-term management of AMI patients. Nevertheless, even with current findings we believe that more resources and attention should be shifted towards ambulatory follow-up focusing on secondary prevention measures (i.e. optimal control of risk factors and prudent, cost-effective, early detection of subsequent and recurrent manifestations of atherosclerosis), particularly in high risk patients. Furthermore, we recommend reinforcing out of hospital measures for high quality chest pain evaluation such as a dedicated service, for chest pain evaluation (e.g. outpatient chest pain units) with high sensitivity troponin point-of-care essays and non-invasive coronary evaluation tests that would reduce ED visits and in-hospital evaluations.