Background/Purpose: It is unclear whether cognitive
complaints in patients with SLE are indicative of true Cognitive Impairment
(CI) or underlying depression or anxiety.

To
determine: 1) the validity of the patient-reported outcome on CI (Perceived
Deficits Questionnaire – 5-item [PDQ-5]) and 2) the association of PDQ-5 with
self-reported symptoms of depression and anxiety.

Methods:
Consecutive
patients followed at a single centre and seen between Feb 2014 and May 2015 that agreed to participate
were included in this study. Patients
completed PDQ-5, which assessed perceived cognitive deficits from the patient’s
perspective. PDQ-5 included five questions representing four subscales:
Attention/Concentration, Retrospective Memory, Prospective Memory, and
Planning/Organization. Total PDQ-5 score consists of the sum of the raw scores on
these 5 items and could range from 0-20 with higher scores indicating greater
perceived deficit.

Patients
underwent two cognitive screening tests by two trained assessors: Hopkins
Verbal Learning Test-Revised (HVLT-R) via telephone interview and MoCA via
face-to-face assessment. Patients
also completed Center of Epidemiologic Studies Depression Scale (CES-D) and
Beck Anxiety Inventory (BAI).

Prevalence
of self-reported cognitive deficits (PDQ-5), depression and anxiety were
determined and scores from these questionnaires were compared in patients with
and without CI (based on HVLT-R). Sensitivity
(Se)/specificity (Sp) and Positive Predictive Value (PPV)/Negative Predictive
Value (NPV) of PDQ-5 in detecting CI (based
on HVLT-R and MoCA), depression (CES-D)
and anxiety (BAI) were studied.

Results:
Of 71 patients, 46%
self-reported cognitive difficulties occurring ‘often’ or ‘almost always’ in at
least one of PDQ-5’s four subscales. 45% reported depressive symptoms by CES-D,
and 24% reported moderate-severe anxiety by BAI.

CES-D
showed higher scores in CI patients compared to those without CI (22.1±13.7 vs. 15.9±10.6, p=0.02)
[higher scores = more depressive symptoms]. There were no significant
differences in BAI or PDQ-5 scores between patients with and without CI.

Se, Sp,
PPV and NPV were high in both CES-D (Se 69%, Sp 75%, PPV 63%, NPV 79%) and BAI
(Se 94%, Sp 69%, PPV 48%, NPV 97%) signifying that PDQ-5 is detecting anxiety
and depression.

PDQ-5 was
less predictive of objective CI (MoCA: Se 58%, Sp 60%, PPV 53%, NPV 65%;
HVLT-R: Se 48%, Sp 52%, PPV 41%, NPV 59%) (Table 1)

TABLE
1. Sensitivity, specificity, PPV and NNP of PDQ-5 in detecting CI (HVLT-R and
MoCA), depression
(CES-D) and anxiety (BAI)

Conclusion:
The PDQ-5
self-report questionnaire is not a valid test to screen for CI in SLE. Depression and anxiety among SLE
patients was highly prevalent using CES-D (46%) and BAI (24%) and depression
was associated with CI. Patients’ cognitive complaints reported in PDQ-5 scores
were not reliably associated with performance on MoCA or HVLT-R, but rather were influenced by the presence
of depression and anxiety.