title: Outcome correlation of smear-positivity but culture-negativity during standard anti-tuberculosis treatment in Taiwan.
abstract: BACKGROUND
  The appearance of smear-positivity but culture-negativity (SPCN) for acid-fast bacilli among sputum specimen is frequently found in pulmonary tuberculosis (TB) patients during treatment. This study aimed to investigate clinical risk factors, impacts on treatment course, and relapse pattern associated with sputum SPCN.
  
  
  METHODS
  We retrospectively enrolled 800 patients with culture-proven pulmonary TB who were receiving standard treatment and follow-up at six TB-referral hospitals in Taiwan between January 2006 and December 2007. Relevant patient characteristics and chemotherapy data were analyzed for associations with incidence of SPCN. Data from patients who relapsed within 3 years after completing treatment were analyzed for associations with SPCN during treatment.
  
  
  RESULTS
  Of the 800 subjects, 111 (13.8%) had sputum SPCN during treatment. Three factors were found to predict the development of SPCN; namely, high initial acid-fast staining grading (OR, 3.407; 95% CI, 2.090-5.553), cavitation on chest-X ray films (OR, 2.217; 95% CI, 1.359-3.615), and smoking (OR, 1.609; 95% CI, 1.006-2.841). Patients with SPCN had longer treatment duration (rifampicin: 284 ± 91 vs. 235 ± 69 days, P <0.001; isoniazid: 289 ± 90 vs. 234 ± 69 days, P < 0.001) than those without SPCN. Finally, the rate of relapse within 3 years of completing treatment was similar for groups with/without SPCN (2.7%, 3/111 vs. 1.0%, 7/689, respectively; P = 0.15).
  
  
  CONCLUSIONS
  In conclusion, severity of infection was a major risk factor for SPCN during treatment; however, the relapse rate within 3 years of completing treatment was not affected by the appearance of SPCN.
authors.affiliation: Institute of Clinical Medicine, National Cheng Kung University Medical College, Tainan, Taiwan. cwc081@hotmail.com.|Department of Internal Medicine, Taichung Veteran General Hospital Chiayi Branch, Chiayi, Taiwan. cwc081@hotmail.com.
authors.forename: Wen-Cheng
authors.initials: WC
authors.lastname: Chao
authors.affiliation: Chang-Hua Hospital, Ministry of Health and Welfare, Changhua, Taiwan. hiwen@chhw.mohw.gov.tw.
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Huang
authors.affiliation: Department of Internal Medicine, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan. mingchih@w.tmu.edu.tw.
authors.forename: Ming-Chih
authors.initials: MC
authors.lastname: Yu
authors.affiliation: Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan. taic3057@gmail.com.
authors.forename: Wen-Ta
authors.initials: WT
authors.lastname: Yang
authors.affiliation: Tao-Yuan Hospital, Ministry of Health and Welfare, Tao-Yuan, Taiwan. dejavu1114@gmail.com.
authors.forename: Chou-Jui
authors.initials: CJ
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, Buddhist Tzu Chi General Hospital, Tzu Chi University, Hualien, Taiwan. e0139@tzuchi.com.tw.
authors.forename: Jen-Jyh
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Hua-Lien Hospital, Ministry of Health and Welfare, Hualien, Taiwan. hrm@hwln.mohw.gov.tw.
authors.forename: Ruay-Ming
authors.initials: RM
authors.lastname: Huang
authors.affiliation: Institute of Clinical Medicine, National Cheng Kung University Medical College, Tainan, Taiwan. cshieh@mail.ncku.edu.tw.
authors.forename: Chi-Chang
authors.initials: CC
authors.lastname: Shieh
authors.affiliation: Chest Hospital, Ministry of Health and Welfare, #864, Zhongshan Rd, Rende District, Tainan, 717, Taiwan. chientb8@mail.ccd.mohw.gov.tw.
authors.forename: Shun-Tien
authors.initials: ST
authors.lastname: Chien
authors.affiliation: Chest Hospital, Ministry of Health and Welfare, #864, Zhongshan Rd, Rende District, Tainan, 717, Taiwan. jychien@ntu.edu.tw.|Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan. jychien@ntu.edu.tw.
authors.forename: Jung-Yien
authors.initials: JY
authors.lastname: Chien
mesh_terms: D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013183:Sputum / Q000382:microbiology*; D013624:Taiwan; D013997:Time Factors; D016896:Treatment Outcome; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000188:drug therapy
chemical_list: D000995:Antitubercular Agents