TB-related technical enquiries received in Japan, 2017–2019

Abstract

SETTING:

Japan, an intermediate TB burden country.

OBJECTIVE:

To review TB-related technical enquiries received at the Research Institute of Tuberculosis, Japan, from January 2017 to December 2019.

DESIGN:

This was a cohort study.

RESULTS:

A total of 2,197 enquiries were analysed. On average, 61.0 enquiries/month (range: 42–81) were received. The enquiry rates were highest for the Yamanashi (4.65/100,000 population) and Ishikawa (4.55) Prefectures, and lowest in the Yamagata (0.46) and Tochigi (0.56) Prefectures. The main organisations the enquirers belonged to were local governments (n = 1,585, 72.1%) and healthcare facilities (n = 307, 14.0%). The enquirers were medical doctors (n = 391, 17.8%), nurses (n = 1,207, 54.9%), other healthcare professionals (n = 57, 2.6%), the general public (n = 168, 7.6%) and others/unknown (n = 374, 17.0%). The most frequent enquiries were about TB diagnosis and treatment (n = 501, 22.8%), including laboratory diagnosis (n = 88, 4.0%), TB treatment in general (n = 93, 4.2%) and management of comorbidities (n = 86, 3.9%), followed by contact investigations (n = 385, 17.5%) and TB in foreigners (n = 344, 15.7%).

CONCLUSION:

As the most frequent enquiries were about diagnosis and treatment of TB, the health ministry of Japan should maintain a few specialised TB institutions with TB physicians to provide technical assistance.

In Japan, the TB notification rate has decreased 70-fold in the past seven decades from 698/100,000 population in 1,951 to 11.5/100,000 population in 2019.^1,2 However, about 5,000 smear-positive pulmonary TB cases are reported every year,³ with over 65% involving persons aged ⩾65 years. These potentially infectious TB cases pose a public health threat to the community, such as TB outbreaks.^4–8 To prevent and detect TB outbreaks early, local health offices are responsible for conducting contact investigations for diagnosed cases^9–11 under the Communicable Disease Control Act of 1998.¹² TB among immigrants is also a challenge in eliminating TB in Japan, with the proportion of immigrants among all TB cases steadily increasing from 2.4% in 2000 to 10.7% in 2019.³ Immigrants accounted for 73.1% of the TB cases among those aged 20–29 years in 2019.³

The Research Institute of Tuberculosis (RIT), Tokyo, Japan, receives nearly 700 technical enquiries concerning TB every year from healthcare workers of local health offices and healthcare facilities all over the country; all communications, including responses, are electronically stored in a computer server. These enquiries reflect the interests and concerns of frontline healthcare workers. However, there has not been much detailed analysis conducted, except that we previously reported on enquiries received at RIT in 2014–2016, about half of which were related to diagnosis and treatment of TB and TB contact investigation.¹³ As the number of TB cases declines in Japan, the number of TB experts may also decrease at a similar or much faster rate. However, the national TB programme (NTP) needs to retain clinical and epidemiological expertise in TB control to respond to enquiries.

The present study aims to analyse and categorise TB-related enquiries received by RIT in Japan from January 2017 to December 2019 and share the results, particularly with other intermediate TB burden countries, who may experience similar challenges in the near future.

METHODS

This is a descriptive study of TB-related enquiries in terms of time, place and classification, with analyses of correlations of the number and rate of the enquiries with the time the enquiries were received and TB notification rates of prefectures, respectively. The RIT has been receiving enquiries and providing technical assistance on TB, including clinical and public health issues through its website¹⁴ and by telephone. Announcements are normally made during training courses stating that RIT welcomes enquiries and provides consultations. These training courses accommodate more than 2,000 participants and are held annually at RIT, as well as locally, with attendance of RIT staff members. When an enquiry is received by email or telephone at RIT, one of the primary responders (two physicians and three nurses) on duty replies. If more expert opinion is needed, the enquiry is forwarded to other staff members, including a consultant physician, an epidemiologist and two medical micro-biologists. Summaries of the telephone communications are recorded in a logbook. At the end of each month, an administrative staff member reminds all the responders to record their telephone communications in the logbook.

An enquiry was defined as an event in which RIT receives a telephone call or an email containing an enquiry on TB, such as one related to diagnosis and treatment, including laboratory diagnosis, and TB control, from January 2017 to December 2019.

A database of the enquiries has been established and maintained using MS Excel 2010 (Microsoft Corp; Seattle, WA, USA) and the date, the organisation to which the enquirer belongs, the profession of the enquirer, the initial classification of the enquiry and a summary of the enquiry were extracted from the email communications and the logbook of the telephone communications and recorded every month. The names of the enquirers were not initially entered in the database to protect their confidentiality. We classified one enquiry into two categories only if the enquiry explicitly included two independent queries and only if they were not related to each other. Two researchers (AY and MU) independently reviewed the database, particularly the classifications, and reclassified them if it was deemed necessary. A third researcher (YH) decided the final classification if the decisions of the two researchers conflicted. If one or multiple follow-up communications were recorded, only the initial communication was counted when the follow-up communication(s) arrived within 1 month of the previous communication. Administrative, rather than technical, communications, such as requests to send a lecturer for training sessions, requests to conduct laboratory tests or requests to conduct interviews by media, were excluded from the analysis. Communications regarding non-tuberculous mycobacteria (NTM) were also excluded from the analysis, as the primary objective of the study was to provide the background information for TB control in the country.

The correlations of enquiries by month and of enquiry rates and TB notification rates per 100,000 population among the prefectures were analysed using Pearson’s correlation coefficent. Student’s t-test was used for comparisons of means. R software (The R Foundation, Vienna, Austria) was used for these statistical tests. In calculating the enquiry rates and TB notification rates by prefecture, the 2018 estimated population by prefecture (downloaded from the National Statistics Bureau of Japan, Tokyo, Japan) was used.¹⁵ The number of TB cases by prefecture was obtained from routine surveillance data.³ We obtained permission for this study from the institutional research board of RIT, Tokyo, Japan (#RIT-2022-11).

Ethics statement

We obtained a waiver of the ethical review for the study from the Institutional Review Board of the Research Institute of Tuberculosis, Tokyo, Japan (RIT/IRB 22-11) as the study was retrospective and involved the secondary use of data that had already been collected during the course of routine operations.

RESULTS

A total of 2,904 communications (4.0 per working day) was initially entered into the spreadsheet. Of these, 432 were later determined to be administrative, 29 were from overseas and 246 were follow-up communications, leaving 2,197 enquiries for analysis. Communications were mostly received by email (n = 1,519, 69.2%); however, there were some enquiries made via telephone calls (n = 678, 30.8%).

Figure 1 shows the time distribution of the number of enquiries per month. We received an average of 61.0 enquiries per month (range: 42–81) from January 2017 to December 2019, with no statistically significant increasing or decreasing trend (R = −0.016, 95% confidence interval [CI] −0.34 to 0.31).

FIGURE 1.

Number of enquiries received per month at RIT, 2017– 2019, Japan (n = 2,197). RIT = Research Institute of Tuberculosis.

The geographic distribution of the enquiry rates is shown in Figure 2. The enquiry rate was highest (4.65/100,000) for Yamanashi, followed by Ishikawa (4.55) and Miyagi (4.53) Prefectures, and lowest for Yamagata (0.46), followed by Tochigi (0.56) and Okayama (0.63) Prefectures. There was no correlation between the enquiry rates of the prefectures and their TB notification rates (R = −0.024, 95% CI −0.31 to 0.26).

FIGURE 2.

Geographic distribution of enquiries received per 100,000 population at RIT, 2017–2019, Japan. RIT = Research Institute of Tuberculosis. The gradation of darkness indicates the number of enquiries per 100,000 population received from each prefecture by RIT.

Enquirers belonged local governments (n = 1,585, 72.1%), healthcare facilities (n = 305, 13.9%) and unknown/others (n = 307, 14.0%). A total of 740 different organisations were represented. Enquirers’ professions included medical doctors (n = 391, 17.8%), public health and clinical nurses (n = 1,207, 54.9%), other healthcare professionals (n = 57, 2.6%), including veterinarians, the general public (n = 168, 7.6%) and others/unknown (n = 374, 17.0%).

Enquiries were related to TB diagnosis and treatment, including laboratory diagnosis (n = 501, 22.8%) and contact investigations (n = 385, 17.5%), including outbreak investigations (n = 24, 1.1%) and TB in foreigners (n = 344, 15.7%), including TB control policies overseas (n = 39, 1.8%) (Figure 3). Enquiries related to TB diagnosis and treatment were further classified as TB diagnosis in general (n = 43, 2.0%), laboratory diagnosis (n = 88, 4.0%), anti-TB treatment in general (n = 93, 4.2%), management of comorbidities (n = 86, 3.9%), selection of anti-TB drugs unrelated to management of multidrug-resistant TB (MDR-TB) when standard regimens could not be used (n = 25, 1.1%), treatment duration (n = 59, 2.7%), treatment of extrapulmonary TB other than TB pleuritis and TB in lymph nodes (n = 53, 2.4%), management of MDR- and rifampicin-resistant TB (n = 29, 1.3%) and others (n = 25, 1.1%).

FIGURE 3.

Classification of TB-related inquiries received at the RIT, 2017–2019, Japan (n = 2,197). LTBI = latent TB infection; BCG = bacille Calmette-Guérin; RIT = Research Institute of Tuberculosis.

DISCUSSION

We conducted a review of enquiries about TB received domestically at RIT from 2017 to 2019. The majority of the enquiries were concerned with diagnosis and treatment of TB, including laboratory diagnosis, contact investigations and TB in foreigners. Almost three fourths of the enquiries were from local governments and only one seventh were from healthcare facilities. There were substantial differences in the geographical distribution of the enquiry rates by prefecture, ranging from <1/100,000 population to almost 5/100,000 population.

The authors previously conducted a similar study on enquiries received at RIT from 2014 to 2016, and found that a total of 1,864 enquiries (621.3 per year) were received for the 3 years from all over Japan.¹³ Compared to the previous study, the current study found 339 (113/year) more enquiries (15.4% more, P = 0.004). The areas of the enquiries were similar: about one quarter of them were related to TB diagnosis and treatment, followed by contact investigations (about 20%);⁹ however, the proportion of the enquiries related to TB in foreigners, which was about 10% in the previous study, increased in the current study by 51% (95% CI 28–79). No other similar studies analysing enquiries received at the national level seem to exist, in or outside Japan.

One of the reasons why many enquiries were related to TB diagnosis and treatment is that general physicians, even pulmonologists, now have less expertise in diagnosing and treating TB than in the past because the number of TB patients has decreased and the enquiries may not have been resolved at the local level.¹³ Frontline healthcare workers, including those at local health offices, may not have received regular training in TB, a situation similar to that observed in the United States.¹⁶ Another reason may be that over two thirds of TB patients are elderly and are more likely to present with uncharacteristic signs and symptoms (causing the diagnosis to be missed), have adverse reactions to anti-TB medications because of relative frailty, have multiple age-related pathologies and experience drug-drug interactions.^17–19 In addition, elderly people may need special arrangements because of their underlying diseases, such as the use of all injectable anti-TB medications due to the inability to take food orally. Physicians may thus need to deal with complicated situations that require the advice of experts. Enquiries related to contact investigations comprised the second largest type of enquiry because it is sometimes challenging for public health professionals of local health offices to decide the scope of a contact investigation and they might require guidance by expert epidemiologists. The reason behind this is that, as the incidence of TB declines, local health offices, particularly cities with small to medium-sized populations of perhaps less than 1 million in their catchment areas may not have many smear-positive TB cases within their jurisdictions and thus may not have much experience in contact investigations, including outbreak investigations. Those staff members who are experienced in contact and outbreak investigations may gradually and occasionally be transferred to other jobs inside health offices, and this is another reason why technical assistance from experts is necessary. As the issue of TB in foreigners has become pressing in the past decade, enquiries related to TB in foreigners were the third major topic of the enquiries;³ these increased by 50% compared to the 2014–2016 period.¹³ The substantial differences in the geographical distribution of enquiry rates in the prefectures might reflect the ease of access to local expert TB physicians, rather than the actual TB notification rates in the prefectures. The number of inquiries increased in 2017–2019 compared to 2014–2016, likely due to the fact that access to local expert TB physicians for technical assistance may have been more difficult than the earlier period, prompting enquirers to turn to RIT.

Our study had both strengths and limitations. One of the strengths is that we reviewed enquiries received over a period of 3 consecutive years and compared the results with the previous 3-year period; sampled enquiries are therefore likely to be representative of enquiries on TB at the national level and demonstrate the difference in the 3 later years. However, some basic enquiries were probably settled at the local level,²⁰ and these may not have been included in our study. The system of classifying enquiries might appear arbitrary, particularly the multiple categories of TB diagnosis and treatment, and of TB control; however, we have tried our best to accurately classify these enquiries and we consider the classification reflects the reality of TB-related enquiries at the national level.

As most enquiries were related to TB diagnosis and treatment, we believe that the Ministry of Health, Labour and Welfare (MHLW) of Japan should maintain a few specialised TB institutions with expert TB physicians and medical microbiologists at the national or sub-national level to provide technical assistance, including training, education and medical consultation to local governments and frontline healthcare workers.²¹ In addition, the specialised TB institutions should provide local health offices with technical assistance on TB contact and outbreak investigations, including epidemiological assistance, as is done in the United States.²²

Funding Statement

This study was implemented as part of routine activities of technical assistance of RIT and was mostly funded by the Ministry of Health, Labour and Welfare of Japan; however, a part of spending was supported by the Japan Agency for Medical Research and Development, Tokyo, Japan (Grant no. JP22fk0108127).