Sputum smear microscopy diagnosis is one of the key pillars of strategies for tuberculosis control. Unfortunately, the smear positivity depends on time of sputum collection, the number specimens to be examined, and the load of bacilli in specimen [
Smear positive PTB diagnostic dropout cases are more common in TB prevalent setting. Studies conducted in Africa at different setting showing 6 to 38% TB cases failed (dropped out) from diagnostic pathway (loss to follow-up during diagnostic period) [
Retrospective patient record review was conducted in Addis Ababa city covering the period from October 2011 to March 2016. Addis Ababa city Administration has a population of 3,384,569, with annual growth rate of 3.8% [
Thirteen health facilities’ laboratories (10 health centres and 3 hospital laboratories) providing tuberculosis diagnostic and treatment service and those which have records of Ziehl-Neelsen (ZN) stained smear microscopy resulting from October 2011 to March 2016 were included in the current study. Individual patients data documented in the TB record book of these laboratories were used as study subjects.
Health institutions were selected using simple random sampling with the plan of obtaining three hospitals from six public hospitals and ten health centres (one from each subcity). The health facilities’ sputum smear microscopy records, from a period of 2011 to 2016, were used as data source. Status of the record was assessed during reviews of records.
All PTB cases having complete records in the laboratory, from the years 2011 to 2016, were included. However, follow-up case, any form of TB other than PTB, TB laboratory results performed by other than ZN technique, and incomplete records were excluded from analysis.
The collected data were checked for completeness and consistency and computerized using Epi-info software. The data were coded and analysed using SPSS version 20.0 (SPSS Inc., Chicago, USA) software. Descriptive numerical summaries were used to present the findings of sociodemographic characteristics and trends of pulmonary tuberculosis diagnostic dropout rate. Association between the dropout rate and demographic variables was assessed by Chi-square (X2). Bivariate model using Odds Ratio (OR) with a 95% Confidence Interval (CI) was calculated after excluding missing data to identify factors associated with the smear positive PTB diagnostic dropout rate. P-value less than 0.05 was taken as statistically significant.
Before extracting data from records, data collectors were adequately trained and they were instructed to check the completeness of each data before submission. Quality of data collection process was supervised and monitored by the principal investigator.
During the target period 41,884 presumptive TB patients were registered for sputum smear microscopy examination in the study health facilities. Among these patients 2,463 were positive for the first spot sputum samples. Of these first spot positive TB cases, 1,291(52.4%) were males, 70(2.8%) were below the age of 15 years, and 594(24.1%) were above 35 years. Records were incomplete for 194(7.8%) on patients age and 95(3.9%) on patient sex [Table
Socio demographic characteristics of Smears positive PTB diagnostic dropout rate at public health facilities in Addis Ababa, Ethiopia, from 2011-2016.
Variables | Number | Percent | |
---|---|---|---|
Age group in year | <15 | 70 | 2.8 |
15-18 | 170 | 6.9 | |
19-35 | 1435 | 58.3 | |
36-55 | 456 | 18.5 | |
>55 y | 138 | 5.6 | |
Data missing | 194 | 7.9 | |
| | | |
Sex | Male | 1291 | 52.4 |
Female | 1077 | 43.7 | |
Data missing | 95 | 3.9 | |
| | |
Of 41,884 presumptive TB cases recorded in the laboratory registration book in the period from the year 2011-2016, 2,463(5.9%) were smear positive for the first spot sputum samples. Among 2,463 first spot smear positive TB cases, 142 (5.8%) and 298(12.1%) did not get back (dropout) to submit morning and second spot sputum specimen, respectively. Overall sputum smear positive diagnosis dropout rate was 17.9% (440/2463); no patients had dropped out for both sputum (the morning and the second pot). The diagnostic dropout rate for morning sputum positive specimen in hospitals was 5.6% (58/1,039) and in health centres was 5.9% (84/1,424). However, higher proportion of dropout rate for second spot sputum positive specimen in hospitals was 16.4% (170/1,039) compared to the health centres, 9.0% (128/1,424). Percentage dropout for morning positive specimen was 5.7% (4/70) in the younger age group (i.e., below the age of 15 years) and 5.6% (33/594) in the older age group (i.e., above 35 years of age). Similarly, percentage dropout for second spot positive specimen was 7.1% (5/70) in the younger age group and 12.8% (76/594) in the older age group. Diagnostic dropout rate for morning positive specimen was 72/1,291(5.6%) among males and 60/1,077(5.6%) among females. The dropout rate for second spot positive specimen was 154/1,291(11.9%) among males and 126/1,077(11.7%) among females [Table
Mono-variate analysis the association between dropout rate and age, sex, health facility and period of registration of sputum smear positive PTB at public health facilities in Addis Ababa, Ethiopia, from 2011-2016.
Independent variables | First sputum AFB positive | Not submit the | Not submit the | Not submit the morning or | p –values | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
n | % | OR | 95%CI | n | % | OR | 95%CI | n | % | OR | 95%CI | |||
| | | | | | | | |||||||
| ||||||||||||||
< 15yr. | 70 | 4 | 5.7% | 1.03 | 0.35-3.00 | 5 | 7.1% | 0.52 | 0.20-1.34 | 9 | 12.9% | 0.66 | 0.32-1.36 | 0.236 |
15 - 35yr. | 1605 | 90 | 5.6% | 1.01 | 0.69-1.49 | 182 | 11.3% | 0.87 | 0.65-1.16 | 272 | 16.9% | 0.91 | 0.71-1.16 | |
> 35yr. | 594 | 33 | 5.6% | 1 | 76 | 12.8% | 1 | 109 | 18.4% | 1 | ||||
| 194 | 15 | 7.7% | 35 | 18.0% | 50 | 25.8% | |||||||
| ||||||||||||||
Male | 1291 | 72 | 5.6% | 1 | 154 | 11.9% | 1 | 226 | 17.5% | 1 | ||||
Female | 1077 | 60 | 5.6% | 1 | 0.7-1.42 | 126 | 11.7% | 0.98 | 0.76-1.26 | 186 | 17.3% | 0.98 | 0.79-1.22 | |
| 95 | 10 | 10.5% | 18 | 18.9% | 28 | 29.5% | |||||||
| ||||||||||||||
Hospital | 1039 | 58 | 5.6% | 0.94 | 0.62-1.33 | 170 | 16.4% | 1.98 | 1.55-2.53 | 228 | 21.9% | 1.61 | 1.31-1.98 | <0.001 |
Health Center | 1424 | 84 | 5.9% | 1 | 128 | 9.0% | 1 | 212 | 14.9% | 1 | ||||
| ||||||||||||||
2011 | 540 | 31 | 5.7% | 1 | 73 | 13.5% | 1 | 104 | 19.3% | 1 | ||||
2012 | 491 | 25 | 7.1% | 1.26 | 0.76-2.08 | 66 | 13.4% | 0.99 | 0.69-1.42 | 101 | 20.6% | 1.09 | 0.80-1.47 | 0. 362 |
2013 | 440 | 24 | 5.5% | 0.95 | 0.55-1.64 | 45 | 10.2% | 0.73 | 0.49-1.08 | 69 | 15.7% | 0.78 | 0.56-1.09 | |
2014 | 434 | 26 | 6.0% | 1.05 | 0.61-1.79 | 59 | 13.6% | 1.01 | 0.70-1.46 | 85 | 19.6% | 1.02 | 0.74-1.41 | |
2015 | 348 | 17 | 4.9% | 0.84 | 0.46-1.55 | 37 | 10.6% | 0.80 | 0.50-1.09 | 54 | 15.5% | 0.79 | 0.57-1.09 | |
2016 | 210 | 9 | 4.3% | 0.73 | 0.34-1.57 | 18 | 8.6% | 0.81 | 0.51-1.09 | 27 | 12.9% | 0.83 | 0.61-1.31 |
Among 142 TB diagnostic dropouts for morning specimen, 31/540(5.7%), 35/491(7.1%), 24/440(5.4%), 26/434(6.0%), 17/348(4.9%), and 9/210(4.3%) were in the years 2011, 2012, 2013, 2014, 2015, and 2016, respectively. Whereas among 298 TB diagnostic dropouts for second spot, 73/540(13.5%), 66/491(13.4%), 45/440(10.2%), 59/434(13.6%), 37/348(9.6%), and 18/210(8.6%) were in the years 2011, 2012, 2013, 2014, 2015, and 2016, respectively [Figure
Trends of sputum smears positive pulmonary tuberculosis diagnostic dropout rate from 2011-2016.
In mono-variate analysis, the trends of diagnostic dropout of sputum smear microscopy had no significant changes among the years from 2011 to 2016 (P value >0.05), even though the number of patients diagnostic dropout becomes slightly decreasing to the year 2016 (Table
Mono-variate analysis the association between dropout and registration of sputum submission period at public health facilities in Addis Ababa, Ethiopia, from 2011-2016.
Independent variables | First AFB positive | Not submit the | Not submit the | Not submit the morning or | p –value | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
n | % | OR | 95%CI | n | % | OR | 95%CI | n | % | OR | 95%CI | |||
| | | | | | | | |||||||
Year of sputum submission | ||||||||||||||
2011-2013 | 1471 | 90 | 6.1% | 1 | 184 | 12.5% | 1 | 274 | 18.6% | 1 | 0.229 | |||
2014-2016 | 992 | 52 | 5.2% | 0.85 | 0.61-1.21 | 59 | 5.9% | 0.91 | 0.71-1.17 | 166 | 11.2% | 0.88 | 0.71-1.09 |
In this study diagnostic dropout of sputum smear microscopy had no statistically significant association with sociodemographic variables (P value >0.05), while diagnostic dropout had significant association with facility type (P value < 0.05) (Table
Determinants on sputum smears positive pulmonary tuberculosis diagnostic dropout rate in public health facilities, in Addis Ababa, Ethiopia; from 2011 to 2016.
Variables | Drop out of diagnostic | Crude Odds | P-value | |||
---|---|---|---|---|---|---|
Yes | No | %Yes | Ratio | 95%CI | ||
| ||||||
<15 | 9 | 61 | 12.9 | 1 | ||
15-35 | 272 | 1333 | 16.9 | 1.32 | 0.71-2.45 | 0.380 |
35+ | 109 | 485 | 18.4 | 1.43 | 0.76-2.69 | 0.258 |
| ||||||
Male | 226 | 1065 | 17.5 | 1 | ||
Female | 186 | 891 | 17.3 | 0.99 | 0.83-1.18 | 0.881 |
| ||||||
Hospital | 228 | 811 | 21.9 | 1 | ||
Health Center | 212 | 1212 | 14.9 | 0.62 | 0.51-0.77 | <0.001 |
From the total presumptive TB cases registered for sputum smear microscopy diagnosis, the positivity rate for first spot specimens was 5.9%. Among these first spot positive cases, 17.9% did not come back to the laboratory to submit second and/or third specimens on the next day visit. The diagnostic dropout rate in Addis Ababa was higher than the number that WHO reported. The higher dropout rate was associated with the second sputum spot collection and related to hospital services in comparison to health centres. The diagnostic dropout rate was increased by ages but not significantly.
In the current study smear positivity rate was lower than the previous report of 14.2% in Metehara Sugar Factory Hospital, 9.2% in South East Ethiopia, and 10.4% in North Gondar Zone [
Diagnostic dropout rate for second spot sputum specimen in the current study was higher than 5.8% reported by WHO for new strategy shift, 5% reported in Pakistan, and 10.2% reported in Botswana [
In this study diagnostic dropout rate for second spot sputum specimen in hospital was high as compared to the health centres. Studies conducted in Botswana and South Africa have also reported high dropout rate in hospital [
In this study diagnostic dropout rate in the age ranges of 15-35 years was lower than 39.2% reported from Vietnam among age group of 15–34 years [
This is a study based on a very large size retrospective patient’s record review to determine the conventional sputum smears microscopy diagnostic dropout rate. The result may be used as an input for the national TB control program by providing reliable and accurate conclusions implying the importance of shifting to same-day approach. However, the findings are not without limitations. Results are dependent only on the record review, despite some demography data which was incomplete in the laboratory log books. In addition this study was conducted only in public health facilities and hence does not necessarily illustrate the situation in private health situations.
In this study smears positive PTB diagnostic dropout rate of conventional sputum microscopy was highly compared to WHO reported for the new strategy shift implying the importance of shifting to same-day approach. The results from this investigation reinforce the importance that patients should promptly seek the appropriate medical attention following onset of TB symptoms. This study indicated that a high number of presumptive TB cases failed to submit morning and second spot specimen for laboratory investigation; as a result, a high number of active TB cases were untreated and might be potential source of TB transmission to the community, resulting in potential TB transmission to their close contacts, including those caring for the sick person at the later stages of the disease and with the ever increasing threat of MDR and XDR-TB as well as HIV. Hence, shifting from conventional to same-day sputum microscopy is crucial to minimize the TB diagnostic dropout rate in the study area and others similar setting. Research is needed in the local setting to compare the yield and dropout rates between same-day and conventional sputum smear microscopy approach.
Acid Fast Bacillus (or Bacilli)
External quality assessment
Spot-morning-spot
Tuberculosis
Pulmonary tuberculosis
World Health Organization
Ziehl-Neelsen stain.
The data used to support the finding of this study cannot be shared in a publically available data repository system, because there is no such data repository system in the country. However, the data are available from the authors upon request at any time.
Ethical approval was obtained from Ethics Committee of Addis Ababa City Administration Health Bureau Public Health Research and Emergency Management Core Processes
The authors declare that they have no conflicts of interest.
Daniel Melese Desalegn designed the study, developed the proposal, and led data collection, analysis, and writing up the result. Kumera Terfa Kitila and Girmay Medhin critically review and made progressive suggestions from the design to final writing up of the result. All of the authors were participated in data collection, analysis, and interpretation critically evaluated and approved the manuscript.
The authors would like to thank Addis Ababa City Administration Health Bureau and respective health facilities for their cooperation. Our thanks also extend to data collectors and supervisors for their cooperation during the study period.