| NO | Author | Country and area | N | Default rate | Study type | Population |
| 1 | VAN DER Werf T S (1990) [15] | Ghana | 569 | 10 | Retrospective cohort study | Sputum-smear positive pulmonary tuberculosis (PTB) patients registered between 1984 and 1987 in a rural ambulatory non-supervised service program in Agogo Hospital in the hills of Ashanti, Ghana |
| 2 | Chuah S Y (1991) [17] | Malaysia | 227 | 33 | Retrospective cohort study | Tuberculosis patients in Perak started treatment in 1982 |
| 3 | Menzies R (1993) [18] | Canada | 352 | 16 | Retrospective cohort study | Adult Tuberculosis patients treated at the tuberculosis clinic of Montreal Chest Hospital in 1987-1988 |
| 4 | Me’ndez A P (1997) [66] | USA | 184 | 48 | Retrospective cohort study | All patients in New York City with a first-time positive culture for Mycibacterium tuberculosis in April 1991 were selected |
| 5 | Ngamvithayapong J (1997) [22] | Thailand | 412 | 26 | Prospective cohort study | 1) blood donors who had indicated a desire to know their HIV test result; 2) persons attending the hospital’s anonymous counselling and testing clinic; 3) patients attending the hospital’s outpatient clinics for other illnesses but found to be HIV-infected, and 4) female commercial sex workers |
| 6 | Jochem K (1997) [24] | Nepal | 693 | 14.8 | Prospective cohort study | New cases of Smear positive tuberculosis patients |
| 7 | William J (1997) [20] | USA | 294 | 18 | Retrospective cohort study | All patients treated with outpatient DOT from 1984 to 1994 |
| 8 | KATE C (1998) [67] | USA | 2576 | 5.5 | Cohort study | Adult patients at least (15 yr of age) reportedas having TB in California during 1993 |
| 9 | Comolet T M (1998) [27] | Madagascar | 149 | 25.5 | Case-control study | Sputum positive tuberculosis patient |
| 10 | Tanguis H G (2000) [62] | Spain | 2201 | 13.1 | Cohort study | HIV-infected with TB patients between 1987 and 1996 |
| 11 | Borgdorff M W J (2000) [63] | Netherland | 7529 | 10 | Cohort study | Tuberculosis patient in the Netherlands in the period 1993-1997 |
| 12 | El-Sony A I (2002) [13] | Sudan | 1797 | 16.9 | Cross-sectional study | All persons aged 15 - 49 years with respiratory symptoms seen in the general health services from March 1998 to March 2000,from eight states in Sudan |
| 13 | Tekle B (2002) [76] | Ethiopia | 1367 | 11.3 | A case control study | New tuberculosis patients on DOTS |
| 14 | Edginton M E (2002) [29] | South Africa | 303 | 5.6 | A descriptive study | TB patients and community members in the rural Tintswalo district of the Northern Province of South Africa registered with tuberculosis in the 18-month period |
| 15 | Santha T (2002) [41] | India | 676 | 17 | A community survey | All tuberculosis patients registered from May 1999 through April 2000 |
| 16 | Chan-Yeung M (2003) [53] | China, Hong Kong | 5757 | 8 | Nested case-control study | Patients registered for antituberculous drug therapy in 1996 in Hong Kong |
| 17 | Sophia V (2003) [54] | India | 483 | 25 | Case control study | New and re-treatment smear positive patients followed up till treatment outcome from March to December 1999 and March 1999 to September 2000 |
| 18 | Robert M (2004) [21] | USA | 372 | 12.6 | Prospective cohort study | Culture-positive patients who were reported from 1998-2000 |
| 19 | Chang K C (2004) [31] | China, Hong Kong | 408 | 8.5 | Nested case-control study | All tuberculosis patients registered at the Government chest clinics from 1 January 1999 to 31 March 1999 |
| 20 | Hill P C (2005) [42] | Gambia | 301 | 25.2 | Prospective cohort study | New cases of TB aged > 15 years who started their treatment between 16 October 2002 and 26 November 2003 |