Harris 2005.
| Methods | RCT (parallel design) Study duration: 3 months (3 week intervention period, 2 months postintervention follow‐up) Setting: VA Palo Alto Health Care System, Stanford University and the local community, California, USA |
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| Participants | 163 eligible, 137 randomly assigned, 114 completed Intervention (stress‐writing group): 41; intervention (positive writing group): 37; and control (neutral‐writing group): 36 Age: mean age 43 (SD ± 17.7) years, range not reported Sex: male 49, female 65 Physician diagnosed asthma by history Inclusion criteria: adult patients with physician‐diagnosed asthma and evidence of reduced pulmonary function at baseline Exclusion criteria: younger than 18 years of age, not diagnosed with asthma by a physician, diagnosed with COPD by a physician, post‐traumatic stress disorder and unable to write for 20 minutes and comply with other expectations of study participation, such as getting to weekly writing sessions and assessment meetings |
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| Interventions | Intervention 1: write on a traumatic and upsetting event or loss experienced in life Intervention 2: write on positive experiences such as events that stimulated feelings of happiness or joy Control: write on neutral topics focused on the events of the previous day Participants in all three groups wrote for 20 minutes, once a week, for 3 consecutive weeks. They could write about the same experience at all three sessions or about different experiences. Writing occurred alone in a private room: the first and third writing sessions in the laboratory and the second session in the participant's home |
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| Outcomes | FEV1 and FVC % predicted measured by spirometry according to ATS guidelines, control of asthma (Asthma Control Questionnaire), perceived control of asthma (Perceived Asthma Control Questionnaire), healthcare utilisation and perceived stress (The Perceived Stress Scale) Outcomes measured at baseline, immediately post intervention and at 2 months after writing |
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| Notes | Sample size calculation done The study reports only the measurement of FEV1 and FVC % predicted. On request, the study author supplied information on other outcome measures. Experimental and control groups did not differ at baseline in most demographic characteristics, health behaviours, psychological variables and disease severity; however, group differences did exist in terms of age, education and smoking status. Consideration of smoking status did not change the results for any of the outcome variables Study funded by fellowships from the Department of Veterans Affairs Office of Academic Affiliations to the first study author, and from the Fetzer Institute, Kalamazoo, Michigan, USA, to Dr. Thoresen |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "Patients were randomised to a writing group using computer‐generated, equal‐probability allocation" |
| Allocation concealment (selection bias) | Low risk | "Assignments were kept in sealed envelopes until immediately before the first scheduled writing session" |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | "Participants were not informed about the specific nature of the other writing groups and were not aware whether they were in the control or experimental conditions" |
| Blinding of outcome assessment (detection bias) All outcomes | High risk | "Staff performing the pulmonary function assessments were not blind to the experimental condition" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Dropout balanced in numbers across the three groups (8 in intervention group and 6 in control group) with similar reasons for missing data |
| Selective reporting (reporting bias) | Low risk | Only FEV1 and FVC % predicted reported in the paper; however, information on other outcome measures was supplied by the study author on request (reported in PhD dissertation) |
| Other bias | Low risk | No evidence of further systematic bias |