3. Do changes in notifications over time reflect TB incidence?

Transcription

1 3. Do changes in notifications over time reflect TB incidence? Mehran Hosseini WHO/HQ/Stop TB TB monitoring and evaluation unit

2 Intended use of Health Information Monitor and assess disease trends Guide prevention and intervention programs Inform public health policy and policy makers Identify issues needing public health research Provide information for community and program planning Protect confidentiality while providing information to those who need to know Source:

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5 Yemen Estimated case detection rate of new and relapse cases, WHO vs. participants United Arab Emirates Tunisia Syrian Arab Republic Sudan Somalia Saudi Arabia Qatar Pakistan Oman Morocco Libyan Arab Jamahiriya Lebanon Jordan Iraq Iran Egypt Djibouti Bahrain Afghanistan Participants (2008) WHO (2007)

6 x X= 100/0.25 Estimated 100/0.25= /0.50= /0.75= 133 CDR 25% 50% 75% Reported Year How to use the estimate of case detection rate for years 1997, 2003 and 2008 to estimate TB incidence for all years

7 Estimated % 50% 75% Reported CDR (%)

8 70 Bahrain 1400 Djibouti Incidence_published in 09 report Incidence_upper bound Incidence_revised Notifications_new & relapse Egypt Incidence_low er bound Incidence_published in 09 report Incidence_upper bound Incidence_revised Pakistan Notifications_new & relapse Incidence_low er bound Incidence_published in 09 report Incidence_upper bound Incidence_revised Notifications_new & relapse Incidence_low er bound Incidence_published in 09 report Incidence_upper bound Incidence_revised Notifications_new & relapse Incidence_low er bound

9 90 Qatar 300 Somalia Incidence_published in 09 report Incidence_upper bound Incidence_revised Notifications_new & relapse Lebanon Incidence_low er bound Incidence_published in 09 report Incidence_upper 2006 bound 2008 Incidence_revised Notifications_new & relapse Iraq Incidence_low er bound Incidence_published in 09 report Incidence_upper 2006 bound 2008 Incidence_revised Incidence_low er bound Incidence_published in 09 report Incidence_upper 2006 bound 2008 Incidence_revised Incidence_low er bound

10 Determinants of TB notifications New TB cases, reported by country Afghanistan Changes in case finding efforts (e.g. infrastructure, staff, active case finding efforts) Changes in recording and reporting system Bahrain Quality of recording (e.g. misclassification, completeness) and, Quality of reporting (e.g. coverage, completeness, duplicated reporting) Changes in TB case definitions Morocco Changes in incidence

11 Changes in case finding efforts Pulmonary TB cases/100k/year DOTS Declining notification rate Increasing diagnostic effort Slides examined (k/yr) Suarez, P. G. et al. The dynamics of tuberculosis in response to 10 years of intensive control effort in Peru. J Inf. Dis 184, (2001)

12 Change in case definition, Cuba 16 Change in case definition 14 Notification rate, per 100k

13 Changes in coverage of reporting Bangalore NGO Private Corporate Medical college Other Government Health Department q1 99q2 99q3 99q4 00q1 00q2 00q3 00q4 01q1 01q2 01q3 01q4 02q1 02q2 02q3 02q4 03q1 03q2 03q3 03q4 04q1 04q2 04q3 04q4 05q1 05q2 05q3

14 Reported TB cases/100,000/yr Where Changes case notifcations in TB incidence = true incidence USA Netherlands UK Norway

15 Egypt, notified TB cases (new cases) (NTP + non-ntp) y = 11305e x

16 Egypt, notified TB cases (new cases) NTP (black)+ non-ntp (red) y = 10765e x y = 1493e x

17 What changes in incidence are plausible?????

18 Seek possible explanations for inflection points and changes in direction Severe economic crisis Improved health systems and control? Problems with reporting? Better reporting?

19 Questions 3.1 Have TB notifications been increasing, decreasing or stable over time? 3.2 Were there any changes in case-finding effort and/or recording and reporting that might have affected notifications over time? 3.3 How have factors that may influence TB incidence changed over time, and have they had an impact on underlying TB incidence? 3.4 Based on the information discussed questions 1 through 3, how do you think true underlying incidence has changed over time?

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21 SEARO countries SEARO countries

22 3.1 Have TB notifications been increasing, decreasing or stable over time? Djibouti

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24 3.1 Have TB notifications been increasing, decreasing or stable over time? Tasks: look at the notifications (new cases, new pulmonary cases (also by smear), new extrapulmonary cases), assess their change over time using and indicate the direction and years of the changes in the boxes Please discuss the reasons for any differences in trends between pulmonary and extra-pulmonary notifications. These could be changes in the programme, diagnosis or epidemiology. Do the notifications trend in the same direction or are SS+ notifications moving in a different direction or pace than SS- notifications? Please describe possible reasons for any divergences.

25 3.2 Were there any changes in case-finding effort that might have affected notifications over time?

26 3.2 Were there any changes in case-finding effort that might have affected notifications over time?

27 3.2 Were there any changes in case-finding effort that might have affected notifications over time? The following factors are likely to affect notifications over time as they have an impact on case detection. The number of laboratories doing smear and/or culture The number of NTP staff Expenditure on TB control Suspect rate (examined for TB/TB suspect) Number of slides per patient to diagnose one TB patient Proportion of all pulmonary cases diagnosed through active case finding Proportion of population screened for TB through active case finding Proportion of all notified cases reported by non-ntp Task: Please depict how these factors may have affected notifications in your country in the same way you depicted the changes in notifications in the first exercise

28 3.2 Were there any changes in recording and reporting that might have affected notifications over time? Task: If there have been any changes in the recording and reporting system in your country? Expanded coverage of recording & reporting system Began notifying retreatment cases Began notifying SS- cases Began notifying extra-pulmonary cases Began notifying SS+ cases in children Began notifying SS-/extra-pulmonary cases in children Stopped notifying tuberculin positive individuals (including children) as active TB cases System changed from paper to electronic or electronic to internet-based Began checking for and correcting duplications and misclassifications Other

29 3.3 How have factors that may influence TB incidence changed over time, and have they had an impact on underlying TB incidence?

30 Average number TB cases Central Europe: 5yr+ delay in TB control Albania, Bulgaria, Czech, Hungary, Poland, Romania Average GDP per capita

31 Determinants of changes in TB incidence (cont) Source: Dye C et al. Bull WHO 2009

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34 3.3 How have factors that may influence TB incidence changed over time, and have they had an impact on underlying TB incidence? Task 1: Discuss if any of the following had an affect on TB incidence? HIV prevalence GDP ARV treatment Other risk factors (such as malnutrition, smoking, alcoholism, diabetes, indoor air pollution ) Task 2: Explore if the age-sex structure and trend of notified smear-positive TB cases support your assumption of TB incidence? Has the age distribution of cases changed over time in your country? Has the mean age of cases gotten older or younger? What age range has the highest rate of TB notifications?

35 3.4. Based on the information we have discussed in questions 3.1 through 3.3, how do you think true underlying incidence has changed over time?????

36 USE ONION TOOL TO ESTIMATE TB INCIDENCE AND TREND