TB screening prior to long term care admission: time to choose wisely

I recently had a patient who was accepted for admission into long-term care, and I completed the usual paperwork detailing their active problem list, past history, medications, vaccinations, and last chest x-ray (for TB screening purposes).

A few days later, I received a call from the long-term care home. The patient’s chest x-ray was not done recently enough. I checked the file. It was done 110 days ago. They wouldn’t accept my patient for admission unless they had a chest x-ray from the past 90 days (if under 65, they require a TB skin test if they have never had a previous positive test). “It’s in the provincial legislation” was the rationale. No room for any negotiation, it had to be done.

Every family doctor in Ontario has been in this exact same situation, likely multiple times a year, held hostage to order a test that intuitively seems of very little use. But I wanted to do a deeper dive on this issue to see where the genesis of this policy is, and to see whether changes should be made (spoiler alert: changes should definitely be made).

First, the legislation. Any health unit or long-term care home that makes reference to the legislation cites the same two pieces of legislation, the Long Term Care Homes Act from 2007 and the Retirement Homes Act from 2010. Here are the excerpts that make reference to tuberculosis:

The Long Term Care Homes Act 2007

(10) The licensee shall ensure that the following immunization and screening measures are in place:

1. Each resident admitted to the home must be screened for tuberculosis within 14 days of admission unless the resident has already been screened at some time in the 90 days prior to admission and the documented results of this screening are available to the licensee.

4. Staff is screened for tuberculosis and other infectious diseases in accordance with evidence-based practices and, if there are none, in accordance with prevailing practices. O. Reg. 79/10, s. 229 (10)

Retirement Homes Act 2010

(8) The licensee of a retirement home shall ensure that,

(b) each resident is screened for tuberculosis within 14 days of commencing residency in the home, unless the resident has been screened not more than 90 days before commencing residency and the documented results of the screening are available to the licensee;

(c) each member of the staff has been screened for tuberculosis and all other infectious diseases that are appropriate in accordance with evidence-based practices or, if there are no such practices, in accordance with prevailing practices; and

(d) the screening for each of the infectious diseases described in clause (c) has been done using procedures that accord with evidence-based practices or, if there are no such practices, with prevailing practices. O. Reg. 166/11, s. 27 (8).

A couple of things to note. The legislation makes no specific mention of chest radiography, and does not explicitly state what form of “screening” is compulsory. Is screening for risk factors sufficient, or is it necessary to order a test of some sort?

What do the guidelines say? The Canadian Tuberculosis Standards were last updated in 2013 with the 7th edition, and chapter 15 is the relevant section for this topic (Prevention and Control of Tuberculosis Transmission in Health Care and Other Settings). Table 6 outlines the recommendations for TB screening in long-term care:

“Baseline posterior-anterior and lateral chest radiography on admission for people >65 years old from identified populations.” Which populations? “People known to belong to an at-risk population group listed in the section ′′Identification of patients with active respiratory TB within hospitals′′. Here’s that list:

So nearly all patients admitted to long-term care would meet at least one of these criteria, bring born prior to 1966. The rationale for the 1966 criteria is that the TB incidence rate in Canada prior to 1966 was similar to that in a high TB incidence country. The guidelines therefore state that these patients should have a baseline chest x-ray, but do not specify when this has to be done. There is absolutely no mention in the guidelines to any 90-day cutoff. According to the guidelines, for the TB skin test for those under 65 years old, a negative skin test in the past 12 months is sufficient.

What does clinical common sense dictate? One would think that a clinician should be able to look at the guidelines, look at the patient’s risk factors, and determine whether it is reasonable to repeat a chest x-ray given recent possible exposures. If a 90 year old patient had a chest x-ray during a hospitalization 4 months ago, and hasn’t left their home since, requiring them a repeat x-ray to rule out TB is lunacy. There is no reasonable explanation for why this can’t be left to clinical discretion. Keep in mind that a significant portion of admitted patients to long-term care homes have been hospitalized in the last year, likely receiving at least one chest x-ray, and have been waiting months for admission.

The selective insistence on overly prescriptive TB screening in long-term care homes has always struck me as odd. Yes, patients admitted to long-term care are higher risk for TB than their age-matched cohort. But we don’t insist on chest x-rays for high-risk individuals who are hospitalized for a non-respiratory cause. We don’t insist on chest x-rays for incarcerated individuals unless they will be in jail for over 1 year. We don’t insist on chest x-rays for all individuals spending time in a homeless shelter or drop-in centre. So why are we so militant with screening in long-term care, especially when most long-term care homes would be designated as low-risk according to the guidelines?

The answer is clearly a desire for the ministry to avoid any medico-legal risks, but we need to base our decisions on more than just a fear of litigation. There has not been a single case of LTC-associated TB in London-Middlesex in at least the past two years (health unit is tracking down earlier data for me). Having spoken to local infectious disease experts, that is not necessarily a product of good screening, as they aren’t seeing any significant number of elderly patients with active TB detected through the screening process.

The logic of the “90-day chest x-ray” is also significantly flawed. I will grant that patients born in Canada prior to 1966 are higher risk for TB, and deserve a chest x-ray at some point prior to admission. But if they have been continually asymptomatic, why does this particular time point of admission deserve any further scrutiny? They have been asymptomatic for 50 years or more, and had a chest x-ray done at some point to rule out TB. Do we honestly think we are going to pick up TB that has magically decided to re-activate at the exact point the patient is admitted to long-term care? And what about if another patient has a normal chest x-ray at admission, but develops a non-productive, afebrile (likely viral) cough two months after admission? Is it not more likely that this symptomatic patient has TB than the patient who was asymptomatic at admission with a previous normal chest x-ray? The bottom line is that the hypothetical viral cough patient doesn’t need a chest x-ray, nor does the asymptomatic patient require a chest x-ray at admission if a previous chest x-ray was clear (with no other subsequent high-risk exposures since 1966). They’re both exceedingly low risk for TB.

With the way the legislation reads, I understand why Health Units and long-term care homes are interpreting it as they are, here, here, here, and everywhere. The long-term care homes are understandably fearful of inspections from the Ministry of Health that could find that they are not “compliant” with the legislation. The health units understandably want to be conservative in their recommendations, not leading any of their local long-term care homes to be “non-compliant”.

Without either 1) a change in legislation or 2) a public memo from the Ministry of Health clarifying the legislation and how it will be enforced, we’re not going to see any of the health units or the long term care (or retirement) homes make any changes in what is expected of physicians. Until we see a change from the ministry on this, we’re going to continue to be forced to order low-utility chest x-rays, wasting valuable health care dollars. One lifetime chest x-ray (with a physician review to rule out other subsequent high-risk features) should be sufficient for admission to long-term care in Ontario.