Tuberculosis is still a rare disease in the United States, but when it does occur, delays in its diagnosis often exceed the recommendations of the World Health Organization, according to a new report by Harvard Medical School researchers. published on March 22 in The Lancet infectious diseases.
The typical, or median, delay in experiencing an active TB case was 24 days, according to the study, with most delays between 10 and 45 days. However, the delay was much longer; up to 250 days in some cases.
Unlike latent TB, in which the wearer has no symptoms of the TB bacterium and cannot ingest by others, people with active TB have symptoms and can transmit the disease to humans. other.
The new analysis showed that delays in diagnosis were associated with a higher likelihood of passing the disease to household members. He also found a worrying link between delay in diagnosis and the risk for disease progression.
To reduce the complications of TB and prevent the spread of disease, the WHO calls for the start of screening and prompt treatment for all patients with symptoms suggestive of active TB infection for two weeks or more. longer.
The delays we found would be troubling in any case, but they are not permissible in a well-resourced health care system like the United States. “
Maha Farhat, Principal Investigator and Associate Professor of Biomedical Informatics at the Blavatnik Institute in Harvard Medical School
Farhat is a lung medicine physician at Massachusetts General Hospital.
Although the new study was not designed to find out the reasons behind the diagnostic delay, the researchers say one of the most likely drivers is a lack of awareness among clinicians, possibly due to the rarity of TB in the United States. The classic TB display includes coughing up blood, fever, and night sweats, but TB can also give a number of symptoms that do not fit in this third textbook and can throw doctors off the scythe. , making quick and challenging judgments.
Indeed, the analysis suggests that some of the delay may have been prevented, or at least reduced, confirming the importance of raising clinical awareness. For example, the use of breast imaging and molecular diagnostic tests used a shorter time to diagnose and treat as receiving the care of an infectious disease specialist or lung therapy.
“Our findings highlight the importance of provider continuing education. We found a number of factors related to delays and faster diagnosis,” Farhat said. “This tells us that delays are variable and possible. stop. “
The researchers confirm that while TB is still rare in the United States, it is one of the top 10 leading causes of death worldwide. Anxiously, they note, recent trends show that while the number of active TB infections in the United States has been declining, the pace of decline is slowing. and that TB mortality rates in this country have not been followed by a similar decline. This observation notes that gaps in the ability to diagnose the disease early and treat it quickly could be important contributors, Farhat said.
For their analysis, Farhat and colleagues used data derived from medical insurance claims of nearly 19 million privately insured people, capturing doctor visits over nine years, from 2008 to 2016, with a typical case following seven year.
Of the 18.9 million records in the database, the researchers identified 3,389 people with diagnostic codes that suggested TB. Of those, 738 people ended up receiving a final diagnosis of active TB.
To measure delays, the researchers measured the time elapsed between the first scheduled visit for TB-related symptoms and the start of treatment for TB. The delay was medium-; or as usual-; delayed diagnosis of TB 24 days, ranging from 10 to 45 days after the first visit for symptoms indicative of the disease. Some cases, however, took much longer to judge-; more than 240 days in some cases.
Of the 738 patients with active TB, 65 (nearly 9 percent) progressed to develop respiratory problems, and those with delayed diagnosis were more likely to develop complications. The moderate delay in diagnosis among patients who progressed to one or more complications improved approximately 32 days after the first presentation to a physician’s office. In contrast, those who did not experience complications were usually diagnosed and treated within 23 days. The most common complications included irreversible lung damage, collapsed lungs, fungal lung diseases, and bleeding, a symptom of severe inflammation and airway injuries.
To determine the risk of infecting others, the researchers analyzed the prevalence of the disease among household members of 456 patients with active TB who had one or more dependents covered by the same insurance. Of those, 177 patients with latent TB had another family member. Of the 1,026 household members living with someone with active TB, more than a quarter (286) became infected. Further analysis showed that each week increased additional delays in diagnosis increased the risk for progression of the disease by 20 percent.
Two types of patients appeared to be at increased risk for diagnostic delay-; older people and those with suppressed immunity. The study did not investigate the reasons behind this increased risk, but the researchers said this may be because older people tend to show more variable, abnormal symptoms. or because clinicians may assign their symptoms to other lung diseases common in this group, such as COPD or pneumonia, for example.
Vaccination in individuals with vaccines may be delayed due to unusual, variable symptoms or may arise from susceptibility to infections by several other organisms, which may increase the number of cells Reduce TB present in a test sample and make laboratory diagnosis of TB more difficult. People who gave three or more marks were more likely to be judged more quickly than those who attended with fewer symptoms-; perhaps because the presence of more symptoms raised the suspicion of a physician.
The use of X-rays of the breast or CT scans to image the lungs, the use of a molecular TB test called nuclear acid augmentation, and getting care from a TB expert, are all quick diagnoses. The bottom line for clinicians, Farhat said, is to err on the side of too much testing: The risk of losing TB far outweighs the potential problems of prescribing a very cheap molecular test or X-ray to rule out TB infection.
“If you have a patient with cough, fever, shortness of breath, especially if they were born abroad or you are an older person, you should be prescribed an early chest X-ray and, if you are diagnosed with dysphagia, test TB nuclear acid, “she said.” Yes, these are non-specific symptoms but the key is to think about TB as a potential and remember that it is still present in the United States. “
One encouraging conclusion was that a TB diagnosis was promptly followed up with treatment, usually within three days. The researchers warn that their findings may not capture the full extent of delay because their analysis was based on a set of predefined variables contained in medical claim records, which may be elimination of less common manifestations of disease such as conditions in which TB develops outside the lungs and affects the nervous system.
The design of the study did not allow researchers to monitor transmission outside of a patient’s home, thus assessing the risk of referral to others such as health care workers, for example. Another limitation, the researchers said, arose from the unspecified nature of the data, which does not allow researchers to capture important differences by race and ethnicity, which may be related to delays in diagnosis and treatment. , or country of birth, which presents a different risk for TB.
Nevertheless, the approach highlights the usefulness of medical claims data in monitoring patterns of disease diagnosis, testing, and treatment, Farhat said.
“This is the benefit of big data,” Farhat said. “Properly analyzed, these records can provide us with a wealth of information on clinical care trends, without the need to move additional resources for data collection.”