(TIME.com) -- Getting yearly physicals makes intuitive sense -- routine checkups can pick up early signs of disease and get you on treatment that could save your life. Or can they?
The latest review, published in the Cochrane Library from the The Cochrane Collaboration, shows that such vigilance does not reduce the risk of dying from from serious illnesses like cancer and heart disease, and may cause unnecessary harm instead.
Why? Danish researchers studied 14 long-term trials (with a median follow up of nine years) involving 182,880 people, some of whom were offered general health checks and some who were not.
Nine of the trials found no differences in the number of deaths during the study period between the groups, including deaths from heart disease or cancer, two conditions that are most commonly assessed during checkups.
Overall, the analysis failed to find any differences on hospital admissions, disability, worry, specialist referrals, additional visits to doctors or time off work. One trial did find a 20% increase in diagnoses among those getting more frequent health checks, and others recorded an increase in the number of participants using drugs for hypertension, but these did not translate into better health outcomes.
"From the evidence we've seen, inviting patients to general health checks is unlikely to be beneficial," lead researcher Lasse Krogsbøll of The Nordic Cochrane Centre in Copenhagen, Denmark, said in a statement. "One reason for this might be that doctors identify additional problems and take action when they see patients for other reasons."
Preventive screening remains controversial -- and confusing -- for health care consumers. The intuitive power of screening for disease to prevent it is hard to counter, but the latest evidence, from government health groups such as the United States Preventive Services Task Force (USPSTF), shows that the data don't always support the idea that screening leads to better health.
When factoring things such as the cost of screening and follow up tests to confirm false positive or false negative results, the regular checkups aren't always beneficial.
That's the case with breast or prostate cancer, in which studies show that mammograms or prostate specific antigen (PSA) testing can lead to overtreatment of tumors that are unlikely to cause serious disease during people's lifetimes, but cause unnecessary physical and emotional strain instead.
"It is generally recognized that screening should be based on evidence from randomized trials showing a favorable balance between benefits and harms. In our review we could not find that, and we therefore cannot see any justification for public health programs pushing for routine health checks," says Krogsbøll in an e-mail response.
That leaves doctors and patients with the difficult challenge of figuring out how much testing is enough. The researchers are not advising doctors to discontinue screening and treatment if they believe a patient has a health problem, but they suggest public health care initiatives that systematically offer general health checks to the public in general might not make sense.
That means that physicians may need to spend more time with their patients to better determine their individual risk for certain diseases, something that may require a bigger investment of resources initially, but may pay off in health care savings down the road.
In fact, in a corresponding editorial, Dr. Stephanie Thompson and Dr. Marcello Tonelli from the department of medicine at the University of Alberta, Canada, argue health checkups may be waste of health care resources, advising physicians to proceed cautiously. They write:
"Since patients who seek or are willing to undergo routine screening are generally healthier than those who are not (indicating that general health checks are least likely to reach those who could benefit the most), and because most people do not receive interventions that are known to be beneficial, general health checks do not appear to be a wise use of scarce health care resources."
"...When contemplating screening, practitioners should focus on tests that are targeted to the patient's age, sex, and specific risk factors, and that are supported by high-quality evidence. All screening tests (general health checks or focused screenings based on age, sex, or specific risk factors) have potential for benefits and harms, so consideration of patient preferences is critical, especially for those tests where such preferences vary between individuals or where the overall benefit:harm ratio is less favorable."
The authors conclude that more research is needed to target better methods for identifying disease and to further explore the possible misleading and harmful effects of general health check-ups.
"All in all, we are certainly not seeing the entire picture of the harms," says Krogsbøll.
This article was originally published on TIME.com.