Davidson 2001b.

Study characteristics
Methods	Design: multi‐centre trial, randomised, placebo‐controlled, double‐blind, maintenance treatment study, relapse prevention study for participants undergoing acute and continuation treatment in Brady 2000 and Davidson 2001a Duration of intervention: 28 weeks Placebo run‐in: Not specified Post‐treatment: Not specified
Participants	Setting: At 24 centers in the United States Sample size: 96 randomised to sertraline and placebo Mean age: 43.4 years (21 ‐ 69) Sex: 29 men and 67 women Diagnostic measure: DSM‐III‐R Inclusion criteria: Quote: “The enrollees in the current 28‐week double‐blind study were male and female outpatients at least 18 years of age who had completed the previous 24 weeks of open‐label continuation treatment with sertraline and who met responder criteria at the final two visits. The responder criteria were a Clinical Global Impression improvement score ≤2 (much or very much improved) and ≥30% improvement in the total severity score in part 2 of the Clinician‐Administered PTSD Scale, both indexed against the pretreatment baseline of the original double‐blind acute treatment study. Additional entry criteria required that the patients have no clinically significant abnormalities identified in a physical examination and laboratory testing conducted at the end of week 24 of continuation treatment study and that female patients use medically acceptable birth control throughout the study. The original eligibility criteria that defined the study group have been presented in detail in a previous publication. Briefly, at baseline of the two acute treatment studies, the patients met DSM‐III‐R criteria for a principal diagnosis of PTSD as determined by part 1 of the Clinician‐Administered PTSD Scale. A minimum 6‐month duration of PTSD symptoms was required, as well as a total severity score ≥50 on part 2 of the Clinician Administered PTSD Scale at the end of a 2‐week placebo run‐in period; subjects were thus at least moderately ill" Exclusion criteria: Quote: "Subjects were excluded if they had a current or past history of bipolar disorder, schizophrenia, or organic mental disorder; a primary diagnosis of major depression, OCD, or other anxiety disorders; or alcohol or other substance dependence or abuse in the past 6 months, or if they met other exclusion criteria summarized in a previous report. Concomitant psychotropic therapy, with the exception of chloral hydrate for sleep (not more than two nights per week), was prohibited during all studies in the series. Cognitive behavior therapy was not permitted during any of the trials, and other forms of psychotherapy could not be initiated or ended during a trial" Comorbidity: Not specified Dropouts: Insufficient information to determine 'n' in each group
Interventions	Pharmacological intervention: Quote: “To preserve the double blind from the acute treatment study, all patients were discontinued from their acute‐phase study medication (sertraline or placebo) before initiating open‐label study treatment with a daily dose of 25 mg of sertraline. At the end of the first week, the daily dose of sertraline was increased to 50 mg. Dosing throughout the open‐label phase was flexible, in the range of 50 mg to 200 mg, and was based on clinical response and tolerability. The results of the study of continuation treatment with sertraline have previously been reported"
Outcomes	Primary outcomes: Rates and times to event for 1) relapse, 2) relapse or discontinuation because of clinical deterioration (self‐rated), and 3) acute exacerbation of PTSD Secondary outcomes: CAPS, HAM‐D, QLES Time points: Quote: “Patients were evaluated and rated biweekly during the 28 weeks of double‐blind treatment". Data estimation: Not applicable for primary outcomes (Kaplan Meier survival analysis)
Notes	Dates of trial: Not stated Industry‐funded: Yes. Quote: "Supported by a grant from Pfizer" Medication provided by industry: No Any of the authors work for industry? Yes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	It was reported that the participants were randomised but no mention is made of the method of randomisation Quote: "Ninety‐six patients were randomly assigned, in a double‐blind design, to 28 weeks of maintenance treatment with sertraline (50–200 mg, N=46; 78% were women) or placebo (N=50; 62% were women)"
Allocation concealment (selection bias)	Unclear risk	There was insufficient information provided to determine if study medication allocation was concealed
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	The study was described as "double‐blind", though no information was provided on which parties were blinded and how blinding was achieved Quote: "The study examined the efficacy of sertraline, compared with placebo, in sustaining improvement and preventing relapse over 28 weeks in patients with posttraumatic stress disorder (PTSD) who had completed a 12‐week double‐blind, placebo‐controlled acute treatment study and a subsequent 24‐week open‐label study of continuation treatment with sertraline"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	The study was described as "double‐blind", although no information was provided on blinding of outcome assessors
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	There was insufficient information to determine 'n' in each group. Reasons for treatment withdrawal were provided. No information was provided on sample characteristics at endpoint Quote: "Overall, 60.9% of the patients who received sertraline (N=28) and 40.0% of the patients who received placebo (N=20) completed the study. Reasons for study discontinuation for the patients who received sertraline and for those who received placebo, respectively, were: met relapse criteria, 6.5% (N=3) versus 28.0% (N=14); clinical deterioration, 10.9% (N=5) versus 20.0% (N=10); adverse events, 8.7% (N=4) versus 6.0% (N=3); withdrew consent, 6.5% (N=3) versus 6.0% (N=3); and miscellaneous other reasons, 6.5% (N=3) versus 0% (N=0). Six patients who received sertraline and four patients who received placebo at one study site were excluded from the efficacy analyses because of the institutional review board’s concerns about a study investigator’s lack of participation in performing the required efficacy assessments"
Selective reporting (reporting bias)	Unclear risk	The study protocol was not available for this study
Other bias	Unclear risk	Funding for study provided by industry Quote: "Supported by a grant from Pfizer"