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Lowered Tuberculosis Notifications and Deterred Health Care Seeking During the Sars Epidemic in Hong Kong/Chang and Huang Respond

Posted on: Saturday, 9 July 2005, 03:01 CDT

Chang et al., using National Health Insurance data, reported significant reductions in medical service utilization at the peak of the severe acute respiratory syndrome (SARS) epidemic in Taiwan.1 This finding may be supported by other evidence from Hong Kong: lowered tuberculosis notifications. Our assumption is that deterred health care seeking during the epidemic resulted in the lowered detection, and thus notification, of tuberculosis.

To examine the recent trend of tuberculosis notifications in Hong Kong, we calculated the average monthly number of notifications (incidence) per 100 000 population and its 95% confidence interval from January 1997 to December 2002, using the surveillance data and the midyear population of each year,2,3 and compared the trend with that in 2003. To remove monthly fluctuations, we standardized the 1997-2002 average as 100 for each month (Figure 1).

FIGURE 1-Monthly tuberculosis notification rate in 2003 (solid line) and 95% confidence interval (dotted line) of the 1997-2002 average notification rate standardized as 100.

The number of monthly notifications in 2003 was generally lower than the average for 1997-2002, with apparent reductions during the SARS epidemic in April and May. Absolute difference (the number of notifications in 2003 minus the average for 1997-2002) was -129 in April and -240 in May, while that in other months was -83 on average. The number of notifications was lower in 2003 than in previous years until the end of the year.

During the epidemic, people with possible cases of tuberculosis, like people with other adverse health conditions, must have hesitated to seek treatment at medical facilities. Telephone surveys of 1397 Hong Kong residents conducted throughout the epidemic found that more than 70% avoided visiting hospitals during the epidemic.4

The lowered number of notifications of tuberculosis should not be a reflection of actual reductions in incidence resulting from reduced human contact during the epidemic. Since the incubation period of tuberculosis is relatively long, the effects of reduced contact in preventing the infection, if any, should be revealed much later. Thus, the lower number of notifications during the epidemic more likely owes to deterred health care seeking.

The lower number of notifications may have been observed because of underreporting during the epidemic. Health professionals were possibly too occupied in dealing with the epidemic to report tuberculosis cases to the health authority. We are, however, unsure whether this would explain the notification trend following the end of the epidemic.

In sum, case detection of tuberculosis may have been hindered by the SARS epidemic. People with undetected tuberculosis may have continued spreading the disease while treatment was delayed. We should not overlook such potential health hazards of the epidemic.

Masao Ichikawa, PhD, MPH

Shinji Nakahara, MD, MS

Susumu Wakai, MD, PhD

About the Authors

The authors are with the Department of Community Health, School of International Health, Graduate School of Medicine, University of Tokyo, Japan.

Requests for reprints should be sent to Masao Ichikawa, PhD, MPH, Department of Community Health, School of International Health, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan (e-mail: masao@m.u-tokyo.ac.jp)

doi:10.2105/AJPH.2004.046763

References

1. Chang HJ, Huang N, Lee CH, Hsu YJ, Hsieh CJ, Chou YJ. The impact of the SARS epidemic on the utilization of medical services: SARS and the fear of SARS. Am J Public Health. 2004;94:562-564.

2. Disease Prevention and Control Division, Department of Health. Statistics on communicable diseases. Available at: http:// www.info.gov.hk/dh/diseases/index. htm. Accessed May 7, 2004.

3. Census and Statistics Department. Population by sex. Available at: http://www.info.gov.hk/censtatd/eng/ hkstat/fas/pop/ by_sex_index.html. Accessed May 7, 2004.

4. Lau JT, Yang X, Tsui H, Kim JH. Monitoring community responses to the SARS epidemic in Hong Kong: from day 10 to day 62. J Epidemiol Community Health. 2003;57:864-870.

CHANG AND HUANG RESPOND

In our April 2004 article, we reported significant reductions in the utilization of medical services in Taiwan at the peak of the severe acute respiratory syndrome (SARS) epidemic. Our results suggested that the fear of SARS significantly influenced people's utilization patterns and compromised their access to care. Ichikawa's observation of apparent reductions in tuberculosis (TB) notifications in Hong Kong during the SARS epidemic in April and May of 2003 provide further evidence supporting this conclusion.

More important, Ichikawa's finding raises an interesting question: How did the fear of SARS influence the health care utilization of people with different types of diseases? In medicine, it is common to categorize diseases as acute or chronic. Within each category, diseases can be minor, progressive, or life threatening. Apart from TB, our preliminary analyses found that SARS affected ambulatory care utilization differently depending on the disease. The largest reductions in utilization were observed for minor acute diseases, such as acute respiratory tract infections, and modest reductions were found for chronic diseases that presented no immediate danger, such as diabetes. We found no change in utilization of medical services for life-threatening diseases, such as end-stage renal disease.

One plausible explanation is that, faced with the terrifying risk of SARS infection, patients with minor acute ailments may have been more willing to forgo both necessary and unnecessary ambulatory care than patients with life-threatening diseases. Whereas patients with end-stage renal disease require regular kidney dialysis, patients with diabetes, a stable chronic disease, could easily put off their regular physician visits by asking for long-term prescriptions that allowed them to obtain 3 months' worth of medication at a time. Thus we found considerably larger utilization reductions for patients with diabetes than for patients with life-threatening diseases.

These findings reinforce the need for a thorough and systematic framework for evaluating the impacts of SARS on the general population. Because different diseases have different characteristics, hindered detection or treatment of diseases owing to the fear of SARS may result in different levels of health consequences for different members of the population. It is important to identify not only the overall effects of the fear of SARS on various services and diseases but also the smaller effects of the epidemic on people with different educational backgrounds, socioeconomic statuses, and health statuses. Future research can help advance our knowledge in this regard. A better understanding of the health impacts of the SARS epidemic can help public health agencies prevent avoidable health consequences and allocate resources more efficiently.

Hong-Jen Chang, MD, MS

Nicole Huang, PhD

About the Authors

At the time of the study, Hong-Jen Chang was with the Department of Health, Taipei, Taiwan and National Yang Ming University, Taipei, and Nicole Huang was with the Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, Md.

Requests for reprints should be sent to Hong-Jen Chang, Department of Social Medicine, National Yang Ming University, No. 155, Li-Nong Street, Section 2, Taipei 112, Taiwan. (e-mail: changhongjen@yahoo.com.tw).

doi:10.2105/AJPH.2004.046839

Copyright American Public Health Association Jun 2005

Source: American Journal of Public Health

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