Health related quality of life: a changing construct?
In 186 patients with early colon cancer, we investigated the assumption that the meaning of 'quality of life' (QL) remains constant over time. Within a phase-III trial (SAKK 40/93), patients estimated both their overall QL and a range of disease- and treatment-related domains at five timepoints, comprising three concurrent and 2 retrospective estimates: their pre-surgery QL both before surgery and retrospectively thereafter, and their pre-adjuvant QL both at the beginning of adjuvant treatment and retrospectively about 2 months later, and their current QL 2 weeks thereafter. Multilevel models were developed to determine whether the selected domains made stable contributions to overall QL at the concurrent estimates. The weights of the domains changed over time. They did not differ significantly according to whether patients were considering their concurrent state or reflecting on this state at a later timepoint. In the process of adaptation, patients with early colon cancer substantially change the relative importance of QL domains to overall QL. This finding argues for QL as a changing construct and against the assumption that domain-specific weights are stable across distinct clinical phases.
SIAK Coordinating Center, Effingerstr 40, Bern, Switzerland. jbernhard@sakk.ch
Jürg
J
Bernhard
Adam
A
Lowy
Natascha
N
Mathys
Richard
R
Herrmann
Christoph
C
Hürny
D000328:Adult; D000368:Aged; D017326:Clinical Trials, Phase III as Topic; D003110:Colonic Neoplasms / Q000473:pathology / Q000523:psychology* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D012650:Self Disclosure; D011795:Surveys and Questionnaires