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Table 5 Variables, measurement instruments and data sources

From: Outcomes associated with matching patients' treatment preferences to physicians' recommendations: study methodology

Variable

Measurement Instrument

Data Source

Data Collection Period

Independent Variable

   

PMI

Conjoint analysis survey/Doctors' recommendations

Participants

t 1

PMI

Doctors' recommendations

Participants' medical records

t 1 , t 2 , t 3

Dependent Variable

   

PASI scores

Physician-assessed PASI [17]

Participants' medical records

t 1 , t 2 , t 3

TSQM scores

Self-reported TSQM questionnaire [18]

Participants

t 1 , t 2 , t 3

DLQI scores

Self-reported DLQI questionnaire [19]

Participants

t 1 , t 2 , t 3

Confounders

   

Demographic factors

Standard German demographic questionnaire

Participants

t 1

Sex

Age

Partnership

Living with a partner/living alone

Education

Highest educational attainment

Income

Net monthly household income

Number of household members

Employment status

Full-time

Part-time

Not working

   

Treatment factors

Self-reported questionnaire

Participants

t 1

Currently receiving psoriasis treatment or not

Type of psoriasis treatment (topical, UV therapy, Tablets, injections/infusions)

   

Disease-related factors

Self-reported questionnaire

Participants

t 1

Time since diagnosis

Co-morbidities

Psoriatic arthritis

Depression

Allergy

High blood pressure

Cardiovascular disease

Hyperlipidemia

Chronic lung disease, asthma

Liver disease

Diabetes

Cancer

   
  1. Note: DLQI = Dermatology Quality of Life Index; PASI = Psoriasis Area and Severity Index; TSQM = Treatment Satisfaction Questionnaire for Medication; t1 = initial study visit; t2 = first follow-up study visit twelve weeks after t1; t3 = second follow-up study visit twelve weeks after t2