TNT: You Need It, But Guidelines Won't Give It to You

Kenneth W. Lin, MD, MPH


April 03, 2023

Hi, everyone. I'm Dr Kenny Lin. I am a family physician and associate director of the Lancaster General Hospital Family Medicine Residency, and I blog at Common Sense Family Doctor.

Kenneth W. Lin, MD, MPH

For most of my career, I have precepted residents in primary care clinics. Generally, first-years are scheduled to see a patient every 45 minutes on average, then every 30 minutes after the first 6 months. By the third year, residents are scheduled to see a patient every 15 minutes to approximate the frequency at which patients are routinely seen in practice. Adult health maintenance visits are typically allotted two slots, for a total of 30 minutes.

The gradually increased pace of seeing patients is a challenge for many residents. It requires them to not only perform more focused medical histories and physical examinations but also to address a select handful of issues in patients who may have a long list of health concerns or preventive care needs. Prioritizing tasks into those that are necessary to do today vs those that can be deferred to a follow-up visit is an essential skill that is equal parts art and science. In a previous Medscape commentary, I wrote about a research group's efforts to create visual decision aids to generate individualized estimates of life expectancy gains from various preventive services.

Of course, it's uncommon to have the luxury of focusing exclusively on preventive care in older adults, most of whom have one or more chronic condition. Obesity, diabetes, hypertension, hypothyroidism, chronic obstructive pulmonary disease, coronary artery disease, and chronic kidney disease each has its own set of management guidelines. According to a recent estimate, following all guideline recommendations for chronic diseases plus those for preventive and acute care would require a primary care physician with a nationally representative panel of adult patients to work an impossible 27-hour day. That's another good reason for me to continue seeing children in practice!

In a commentary in The BMJ, Dr Minna Johansson and colleagues argued that guideline panels should explicitly consider the estimated clinician time needed to improve the desired outcome for one person in the targeted population, a metric that they call "time needed to treat" (TNT). For example, to implement a National Institute for Health and Care Excellence (NICE) guideline for UK general practitioners (GPs) about providing advice to physically inactive adults would require 3 hours for one more person to increase their self-reported physical activity. For a patient panel of 2000 adults, the absolute TNT would be 167 hours per GP, representing 15% of yearly total face time with all patients, which seems clearly excessive.

In fact, the US Preventive Services Task Force (USPSTF) does occasionally consider the "opportunity costs" of recommending preventive services. When they first reviewed screening for chronic obstructive pulmonary disease (COPD) in 2008, the USPSTF reasoned that the minimal benefit of screening hundreds of patients to prevent a single COPD exacerbation was at least offset by the time and resources it would take to perform spirometry on every adult with a smoking history, a conclusion that it reaffirmed last year. In contrast to NICE, the USPSTF recommends selectively counseling adults without cardiovascular risk factors to promote a healthy diet and physical activity rather than counseling every single person.

Other US guideline groups would do well to adopt the advice of Johansson and colleagues to consider TNT. Last year, the Women's Preventive Services Initiative (WPSI) recommended counseling every woman aged 40-60 years with normal or overweight body mass index "to maintain weight or limit weight gain to prevent obesity." Though preventing obesity is a laudable goal, I'd prefer to counsel those who are obese and suffering from obesity-related conditions and spend my 15 or 30 minutes with others doing something more valuable, like listening to the patient. As Johansson and colleagues wrote in their commentary, "Healthcare policies also need to account for the time clinicians should spend listening in silence, noticing carefully, and co-creating sensible plans of care with patients".

Having served on several guideline panels in the past, I believe that thoughtfully developed evidence-based guidelines can help family physicians care for patients. But guidelines will never comprise all of medicine, particularly primary care, where following too many well-intended recommendations can sometimes get in the way of being a good doctor.

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