Health checks for employees are a yearly event in most workplaces in Japan. Companies are required by law to provide health checks for their employees, and it is the workers' obligation to undergo such examinations although there is no penalty for failing to do so. A higher rate of participation in workplace health checks is considered as an indication of good employee health management.
The benefits of having regular health checks may seem to be too obvious to dispute. But how is it in reality? In what follows, I will present what is found in the literature.
1. Evidence showing the benefits of health checks
What is the greatest benefit of health checks? The answer would differ depending on to whom we ask the question. But one answer that is likely to be shared by many would be longevity gain. Putting the conclusion first, there is no evidence proving this.
In examining evidence for the effectiveness of various medical interventions including medication and health checks, a randomized controlled trial allows the most accurate evaluation and a meta-analysis of outcomes of multiple randomized controlled trials is regarded as the most reliable evidence for medical interventions.1 The Cochrane Collaboration, an international non-governmental organization promoting evidence-based medicine, has issued a systematic review based on meta-analyses to examine the effectiveness of general health checks.2 "General health checks" here refer to those performed on asymptomatic people.
According to the Cochrane review, general health checks do not reduce mortality, whether total mortality or cancer-caused and cardiovascular disease (CVD) mortality. The findings are based on large-scale evidence, with nine randomized controlled trials analyzed for total mortality and eight for cancer-caused and CVD mortality. However, some critics find them problematic because most of the trials were conducted in or before 1980 and therefore do not reflect the subsequent advancement in medicine, most importantly, the advent of statins, a drug used for the treatment of hyperlipidemia.3
In 2014, the results of another randomized controlled trial were released.4 In the trial called Inter99 and conducted in Denmark for the purpose of prevention ischemic heart disease, a total of 59,616 participants were divided into an intervention group consisting of 11,629 and a control group consisting of 47,987. Invitations for health checks were sent to people in the intervention group and those who responded received individually tailored health checks, with counseling or advice on quitting smoking, dieting, or exercising given to those found with unhealthy lifestyles. If found necessary, they were also referred to an appropriate medical institution. After the 10-year follow-up, no significant difference was found between the intervention and control groups whether in the incidence of ischemic heart disease and stroke or in total mortality, contesting the validity of an approach that combines health checks and lifestyle interventions.
Based on the above findings, there is no evidence of health checks delivering longevity gain.
2. Why is there no evidence?
Why has there been no clear evidence showing the effectiveness of health checks? First, as the spectrum of age of people receiving health checks is large, it may be the case that the vast majority of them are those with a low mortality risk or a low risk of developing serious illness.
Second, having a health check program in place does not necessarily mean that everybody takes advantage of it. For instance, only 52.4% of those invited for health checks in the Inter99 trial actually received health checks, while the ratio was as low as 30% in the case of health checks in England which will be discussed later.5
Third, detecting problems during health checks does not necessarily lead to preventive measures such as changing unhealthy lifestyles. While smoking, excessive drinking, poor diet, and lack of exercise are known to be the four biggest lifestyle problems that are likely to lead to serious illness, it has been pointed out that counselling and advice tend to be unsuccessful in changing people's behavior.6, 7 Most people probably know firsthand that bad habits are hard to break in reality even though they think they should do so.
Fourth, not all of those who were found to have problems during health checks and advised to see a doctor will follow the advice. In the case of the aforementioned health check program in England, only 19% of those found to be at high CVD risk actually received therapy with drugs for hyperlipidemia.5
Fifth, medications for high blood pressure and hyperlipidemia, which are likely to be detected by health checks, are modest in their efficacy. For instance, a Cochrane review found that treatment of hyperlipidemia with statins reduced total mortality by 14 percentage points and stroke morbidity by 22 percentage points.8
Theoretically, health checks have the effect of extending longevity and/or preventing heart disease and strokes. However, when all or some of the above circumstances are present, such effects are unlikely to be confirmed by randomized controlled trials in a statistically significant manner unless conducted on a very large sample.
3. Dispute over the health check program in England
In England, where evidence-based medicine originated, a general health check program was launched in 2009 without clear-cut evidence of its effectiveness based on randomized control trials. It was determined that adults aged 40-74 without pre-existing CVD or diabetes would undergo a health check every five years with the aim of reducing CVD morbidity, while those with high CVD risks would be provided with treatment and/or support for their behavioral changes.5
The program provoked controversy. Pointing to the aforementioned Cochrane review findings, some people argued that continuing the periodic health check program would be a waste of medical resources,9-12 while others insisted that the program would be meaningful on the ground that medications for high blood pressure and hyperlipidemia have notable effects.3,13, 14
As it appears, the controversy has yet to be resolved. An analysis using propensity score matching found that the health check program has had a statistically significant but clinically mild impact.15 This analysis is not based on randomized controlled trials and thus has its limitations. However, with the program already in full operation, it seems to be difficult to conduct randomized controlled trials.
4. Health checks and medical expenditures
Based on what has been discussed thus far, there is no evidence proving the benefit of having a periodic health check program and thus the discontinuation of such a program may lead to more effective use of medical resources. However, this gives rise to another big concern that needs to be addressed: abandoning the health check program—regardless of its effectiveness—may result in an increase in medical expenditures. One hypothetical scenario is that medical bills pile up because disease becomes more likely to be left untreated until it gets serious and costly treatment becomes necessary. Also, medical expenditures may increase because many people continue to receive health checks voluntarily even after the statutory program is discontinued, recognizing its importance in maintaining good health. However, the discontinuation of the statutory program may lead to a decrease in medical expenditures, because it reduces opportunities to be diagnosed with high blood pressure or other health problems, and hence results in fewer hospital visits.
Fast-forward to the conclusion, the impact of health checks on medical expenditures is unclear, just like their effects on the longevity of participants.
Among various studies that examined the effects of health check programs in Japan, one that examined medical expenditures for middle-aged workers found that the cost of medical expenditures was significantly lower for those who undergo health checks more frequently.16 According to another study that analyzed the impact of an enhanced health check program, medical expenditures increased after the enhanced program was introduced in 1988.17 Meanwhile, one focusing on elderly people showed that the cost of medical expenditures was lower for those receiving frequent health checks.18 However, the reliability of those studies is disputable as none of them were based on a rigorous comparison with randomized controlled trials. It seems that medical bills tend to be higher for those not undergoing health checks. However, this may be a result of a reverse causality, i.e., while those who make frequent hospital visits incur high medical costs, they also are less likely to undergo health checks because they have their health checked at the hospital. As such, we need to be careful in interpreting the findings.
In Austria, an econometric study attempted to estimate the causal relationship between health screening and healthcare costs, using an instrumental variable approach.19 According to this study, participation in health screening led to a short-run increase in healthcare costs, medium-run cost savings for outpatients, and no statistically significant long-run effects, with the net impact being an increase in healthcare costs. However, it also points to the possibility that health screening may reduce healthcare costs for relatively young people (about 60 years or younger).
Likewise, in Japan, we might be able to identify, at least to some extent, the causal relationship between participation in health checks and the cost of medical expenditures by employing sophisticated econometric methods such as instrumental variables and propensity score matching approaches. However, my personal view is that unlike randomized controlled trials, which are rather simple in their design, those methods are beyond the understanding of ordinary people including myself. We might be told to believe what the experts say because of their knowledge, but we would not be comfortable with following such advice. In order to ensure that such findings can be used as reliable evidence, there needs to be some sort of due process such as third-party verification, in which independent researchers would be asked to analyze the same data to confirm the findings.
5. Conclusion
No clear-cut evidence exists to determine whether undergoing health checks leads to greater longevity and/or lower medical expenditures. However, the lack of evidence does not mean the non-existence of such effects. It simply means that the existence or non-existence of such effects remain unknown. Ideally, it is desirable—although quite time consuming—to verify the efficacy of health checks by conducting a randomized controlled trial, which would involve asking a large number of those who are currently not subject to statutory health check programs to participate in the trial, dividing the participants randomly into those undergoing health checks and those not, and examining the resulting difference in health status between the two groups. This would be a great step forward in realizing evidence-based healthcare policy in Japan.
