Cochrane Systematic Review: General Health Checks- Are they useful?

Title of the Cochrane Systematic Review: General health checks in adults for reducing morbidity and mortality from disease URL:

Background: General health checks are common in many countries, and are intended to reduce morbidity and mortality from disease. However, many screening tests employed have been incompletely studied. It is important to determine if general health checks do more harm than good.

Objectives: To quantify the benefits and harms of general health checks

Outcome Measures

  • Primary:
    • All cause mortality (Death due to any cause)
    • Disease specific mortality (Death due to a specific disease)
  • Secondary:
    • • Morbidity (e.g. myocardial infarction)
    • • New diagnoses (total and condition-specific)
    • • Admission to hospital
    • • Disability (preferably patient-reported)
    • • Patient worry
    • • Self-reported health
    • • Number of referrals to specialists
    • • Number of non-scheduled visits to general practitioners
    • • Number of additional diagnostic procedures due to positive screening tests
    • • New medications prescribed and frequency and type of surgery
    • • Absence from work

Inclusion and exclusion criteria

  • Inclusion criteria: Randomized Controlled Trials examining the effects of general health checks involving adults regardless of age or ethnicity (race)
  • Exclusion criteria: Randomized Controlled Trials restricted to a specific disease, age group, or elderly only. Observational studies Non-randomized Trials

What did the investigators do? They searched extensively for trials that satisfied the inclusion and exclusion criteria. In all, they identified 16 trials that investigated the effects of general health checks. The trials were commenced/ reported between 1962 and 1999. Most trials were conducted in Europe, while a few were conducted in the USA.

What did they find? There was no difference in morbidity and mortality between those people who were screened by health checks, and those who did not undergo health checks. Therefore, they concluded that general health checks were unlikely to be beneficial.

Points to consider when interpreting the results

1. The trials were conducted in developed countries, all of which had robust health-service infrastructure in place at the time of the trials. No trials performed in developing countries/ countries with poor health-service infrastructure included (probably because they do not exist!). Therefore, the results cannot be generalized to all countries.

2. Single disease/ organ/ organ system screening programs were excluded. Therefore, one cannot presume that such programs are not beneficial- the review does not extend to these programs in the first place.

3. The risks of morbidity/ mortality in the general population are considerably lower than that in a high risk group/ specific age group. In order to demonstrate a significant difference due to general health checks, the already low rates would have to reduce to much lower levels in those undergoing such checks, compared to controls. This is unlikely to happen when observing large numbers of people, and any difference is likely to be small.

4. Except for one study, none of the trials examined the number of new diagnoses made due to the health check. This information is crucial to estimating the ‘yield’ (excess/ additional cases detected) of the screening.

5. Those who underwent health checks often received a different level of care as usually their doctors knew which arm (health check or control) subjects belonged to. Those at risk often received additional counselling/ advice/ intervention from their doctors, reducing the overall number of those with disease. Since the outcome measure was disease, not risk factor, this would not be captured, resulting in a lowering of effect.

6. The trials did not report the number of specialist referrals made following the screening procedures- key indicator of further intervention to limit disease.

7. Many trials had significant loss to follow-up/ attrition bias: in many trials more than 20% subjects failed to complete the trial. Since different proportions were compared in the two arms, the effect would have been affected.

8. All the trials were conducted in countries having existing screening/ intervention programs. It is not known if subjects benefited from those screening/ intervention programs after early detection as part of the trials.

9. Self selection: those who volunteer for such trials/ studies are usually individuals at low risk for health problems (on account of healthier lifestyles, low-risk behaviour, etc.). It is not entirely possible to presume the adult general population is similar.

In addition, typical volunteers for health checks are individuals who are concerned about their well-being. These are often educated, aware persons who adhere to healthy life-styles and are at low risk for disease. Ironically, even in developing countries, those who need screening the most, are often the most likely not to avail such services. I am not entirely convinced that trials conducted in developing countries will generate remarkably different evidence due to this one reason.

In short, the world over, those at risk tend to avoid the health care system for fear of lifestyle restrictions, expensive treatment or both. Unless such individuals avail of screening programs/ general health checks, trials will not demonstrate significant benefit from these activities.

Bottom line?

General health checks are not beneficial to adults in the general population in countries having robust health service infrastructure. The same cannot be said of specific age/ racial/ risk groups, or countries lacking such infrastructure as of now for lack of evidence (it has not been evaluated).

Disease specific screening programs are probably beneficial, but were not the focus of this review, hence it is better to persist with them till evidence to the contrary is available.