Monday, September 30, 2013

Health checks increase diagnoses, but do they improve health?

- Kenny Lin, MD, MPH

After moving into our current home nine years ago, my wife and I purchased a basic security system - the kind with a programmable keypad, multiple door alarms and a motion sensor. The alarm has sounded about a dozen times since then. None of these times was a burglary actually in progress. On several particularly windy days, one of us forgot to lock the back door after leaving, and it blew open. Two or three other times, departing early for work, I accidentally hit "Away" on the keypad (arming the motion detector at the foot of the stairs) rather than "Stay," causing the klaxon to sound when my unsuspecting son came down the stairs later in the morning. We've also set off the fire alarm a few times while cooking. Although our security system cost little to purchase, by now we've spent more money in monitoring fees than the value of what we might conceivably have lost in an actual burglary.

There are intangible benefits to having a home security system - peace of mind being the most important. But our peace of mind has been achieved at the cost of temporarily diverting multiple municipal police and fire units, disturbing our neighbors, receiving inconvenient cellular phone calls from the monitoring company, and terrifying a 5 year-old on his way to breakfast.

I think about my home security system every time I do a physical examination on an apparently healthy adult. Although the general health check is an established medical tradition, a Cochrane for Clinicians review in the October 1st issue of AFP concluded that health checks increase the number of diagnoses but don't reduce morbidity or mortality. So are these visits a waste of time? Not necessarily, argued Dr. Krishnan Narasimhan:

Although the general health check has not been shown to decrease morbidity or mortality, there is some evidence that designating a specific visit for the provision of preventive services may increase the likelihood that patients will receive them. ... Adding preventive services to other patient visits, sending reminders to patients to use these services, and using community linkages, such as screening at job sites or schools, could be potential avenues for effective delivery of preventive services. Evaluating better models for the delivery of evidence-based preventive services is an area for further research.

Unfortunately, a 2012 study in the Annals of Family Medicine found that patients often overestimate the benefits of preventive interventions that primary care physicians commonly provide at health checks: breast cancer screening, colorectal cancer screening, and medications to prevent hip fractures and cardiovascular disease. In most cases, patients' "minimum acceptable benefit" (the lowest level of benefit that in their mind was required to justify the preventive intervention) far exceeded the actual benefit of the service established in randomized trials. Further, the study considered only the benefits of these services, and not the false alarms, which occur, for example, in more than 60 percent of women receiving annual mammography after 10 years.

1 comment:

  1. n = 1 - so clearly IF you happen to be the 1 in 100 (or 1 in 10,000) whose life is saved by some preventive measure - then it was "worth it" that 9,999 others had to take a costly drug with potential for not insignificant side effects and with no potential to benefit .... The "n number" (whatever it is for whatever intervention is contemplated) is what must be balanced by all the other factors (ie, IF your security system was seen by an armed burglar who therefore chose not to force entry into your house while you and your family were there - then perhaps the security system you describe above would have been worth it after all ...). That said - I wonder IF that 2012 Annals of Family Medicine study looked at potential for harm for the preventive interventions it studied? I also strongly suspect that IF not only number needed for potential to benefit was cited to prospective patients - but also: i) reminder made that if potential to benefit is only 1 in 200 - that the other 199 patients get absolutely NO benefit at all; and ii) cost was quantitated and potential for harm (in terms of likelihood of side effects) was clearly stated - that many FEWER prospective patients would opt for a preventive measure. Instead - mass media rather than informed collaborative patient decision-making all too often determines what is to be screened ...