Assessing reliable and clinically significant change on Health of the Nation Outcome Scales: method for displaying longitudinal data.
OBJECTIVE
Many authors recommended that reliable and clinically significant change (RCSC) should be calculated when reporting results of interventions. To test the reliability of the Health of the Nation Outcome Scales (HoNOS) in identifying RCSC, we applied the Jacobson and Truax model to two HoNOS assessments in a large group of people evaluated in 10 community mental health services in Lombardy, Italy, in 2000.


METHODS
The HoNOS was administered to 9817 patients; of these, 4759 (48%) were re-assessed. Reliable change (RC) was calculated using Cronbach's alpha (alpha), as a parameter of the reliability of the measure. Clinical significance cut-offs were calculated using a classification of severity based on HoNOS items.


RESULTS
In the whole sample, the clinical improvement cut-off was 11 and the remission cut-off was 5. Considering the severe patients, the clinical improvement cut-off was 12. The RC index calculated on the whole group and on the subgroup of severe patients indicated that eight-point and seven-point changes, respectively, were needed to be confident that a real change had occurred. Longitudinal changes were depicted on two-dimensional graphs as examples of reporting RCSC on HoNOS total scores in a routine data collection: 91.6% of the whole sample (4361) was stable, 5.6% (269) improved and 1.8% (129) worsened.


CONCLUSIONS
Our study proposes a methodological framework for computing RCSC normative data on a widely used outcome scale and for identifying different degrees of clinical change.
Parabiaghi
Alberto
A
Unit of Epidemiology and Social Psychiatry, 'Mario Negri' Institute for Pharmacological Research, Via Eritrea 62, 20157 Milan, Italy. parabiaghi@marionegri.it
Barbato
Angelo
A
D'Avanzo
Barbara
B
Erlicher
Arcadio
A
Lora
Antonio
A
D005500:Follow-Up Studies; D006801:Humans; D007558:Italy; D001523:Mental Disorders / Q000628:therapy*; D008605:Mental Health Services / Q000592:standards; D017063:Outcome Assessment, Health Care; D011634:Public Health / Q000639:trends*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires