Effect of ageing on interpretation of disease activity measures and on cognition, physical activity and performance in patients with rheumatic disorders.

The rate of the demographic ageing process in the Netherlands will double in
the years to come. The Dutch population is anticipated to grow to 17.8 million
around 2040, of which 4.6 (26%) million people will be 65 years of age or
older. As the *baby-boomers* age, the number of patients with inflammatory
arthritis, including those with rheumatoid arthritis (RA), will also increase.

The evolving demographical transition of the *RA population* makes it necessary
to critically review ageing and comorbidity in RA and the possible impact of
these factors on (1) disease-specific instruments used to make treatment
decisions and (2) cognitive, physical activity and performance.

Currently, it is unclear whether disease activity measures commonly used in
treat-to-target strategies are directly transferrable to elderly RA patients.
Only limited evidence for the effect of ageing on general and disease-specific
RA instruments exists: ageing by itself may have a negative impact on both the
pain Visual Analogue Scale (VAS) and global assessment VAS. Sokka et al.
concluded that only 15% of the general population > 50 years old meet all four
American College of Rheumatology (ACR) remission criteria.

More evidence on how disease instruments behave in elderly individuals, is
therefore urgently needed. To know whether a difference in performance of i.e.
the DAS28 is due an age-effect or due to a change in physiological disease
activity (patient adaptation), population data are needed. In addition, it is
important to gain insight in outcomes that seem relevant but are currently not
explicitly accounted for in the care for elderly RA patients, such as a decline
in cognition, physical activity and performance. These questions will be
answered in the current research proposal.

In the STudying Ageing in Rheumatic diseases (STAR) project, our main goal is
to: study the ageing process in patients with and without RA and specifically
assess the impact of ageing on (1) the interpretation of commonly used measures
of disease activity and (2) cognition, physical activity and performance.
Baseline data from the STAR cohort (population controls and RA patients), which
we aim to set up in the context of this proposal, will be used.

Study design: observational cross-sectional matched case - control study.

In total, 420 RA patients and 420 population controls between 55 and 85 years
of age, stratified according to age at five year intervals, will be included.
These subjects, between 55 and 85 years of age, will fill out (RMD-specific)
questionnaires and undergo cognitive testing.

Part of de participants (n = 240) will also undergo blood analyses, a physical
examination and physical tests.
By comparing the outcomes of RA patients with population controls, we can study
the effect of ageing on the outcome measure.

All participants need to complete generic and RA-specific questionnaires.
Patients > 80 years who are physically unable to complete the whole study
procedure (i.e. geriatric patients who are considered frail by the
rheumatologist / researcher and/or patient itself), are allowed to undergo only
part of the study measurements / questionnaires. For the 240 participants who
also visit the research center for additional measurements, this extra visit
will take about 1 hour. Completing the questionnaires at home (on paper or
online), including a telephone interview, will take 2-3 hours.
All 240 patients and controls will be seen in one study visit by 1-2 trained
research assistant(s), using standardized protocols. Participants will undergo
a physical examination, physical and laboratory (three blood samples; one
venepuncture) testing.
The physical examination, cognitive testing (via telephone interview) and
laboratory tests may reveal prevalent disease, such as hypertension or
cognitive deficits. If any of the participants do not wish to undergo cognitive
testing, he or she will continue according to protocol without having fulfilled
this item and without further consequences. The participant will specifically
be given the opportunity to opt out for cognitive testing. If a participant is
suspected of cognitive dysfunction (TICS score < 34) we will inform the
treating rheumatologist in case of a patient or general practitioner in case of
a control. The rheumatologist or general practitioner can bring this
participant into care for further analyses via the outpatient clinic for
cognitive (dys)function (*geheugenpoli*), after consulting the participant.
With regard to participation risks and benefits: all subject will get after
participation a (telephone) meeting with the researcher to discuss the
findings. Abnormal laboratory values or abnormalities during physical
examination of potential clinical importance will always be discussed with the
patient and the rheumatologist / general practitioner. Awareness of normally
unknown pathology may affect a person*s perception of his/her own health
condition negatively. On the other hand, early detection of for instance
hypertension or cognitive dysfunction has potentially favourable effects on
disease progression and may enable early intervention.