Table 3.
Results of multivariable models to determine predictors of neuropsychological test performance in subjects with SLE
| Variables significantly associated with test performance in subjects with SLE Beta coefficients, β (±SE), are displayed* |
Simple Reaction Time† | Matching Grids† | Match to Sample† | Running Memory Continuous Performance Test (RMCPT) | Spatial Processing (SP) | Non-Spatial Memory (NSM) | Spatial Memory (SM)† |
| Age | – | −0.01**(0.003) | −0.01** (0.004) | −0.60** (0.15) | – | −0.01 (0.01) | −0.01* (0.004) |
| History of psychiatric illness, after the SLE diagnosis, requiring medication prior to current study |
0.29** (0.07) |
– | −0.35* (0.14) | −15.13** (4.86) | – | −0.48** (0.18) | – |
| Increased platelet count† | 0.16* (0.08) | −0.34** (0.09) | – | – | −4.64* (2.10) | – | – |
| History of peripheral thrombosis | – | −0.24* (0.11) | −0.22* (0.10) | – | – | −0.27 (0.15) | – |
| Anxiety score >1–6‡ (vs 0) |
– | – | – | −12.42** (4.06) | −5.36** (1.99) | – | – |
| Anxiety score >0–≤1‡ (vs 0) |
– | – | – | −3.24 (3.27) | −0.85 (1.63) | – | – |
| Some computer experience§ (vs extensive) |
– | – | – | – | – | −0.70** (0.17) | −0.36**(0.11) |
| Moderate computer experience§ (vs extensive) |
– | – | – | – | – | −0.34** (0.13) | −0.08 (0.07) |
| Increased QA/KA ratio | – | – | −0.01* (0.002) | – | – | – | – |
| History of hypertension | – | – | – | – | −2.95* (1.49) | – | – |
| SELENA-SLEDAI score | – | – | 0.01* (0.01) | – | – | – | – |
| Current hydroxychloroquine use | – | – | – | – | 4.78** (1.64) | – | – |
Associations of individual variables with neuropsychological test performance are displayed as beta coefficients, β, ±SEs (parentheses). Empty cells (–) indicate that the individual variable did not associate with performance on that particular test.
β in bold are those with significant p values (*p<0.05; **p< 0.01).
*A positive β indicates worse performance on the Simple Reaction Time test (increased reaction time), whereas for all other tests, a negative β indicates worse performance (decreased throughput scores).
†(Natural) log-transformed variable.
‡Anxiety scores were categorised based on the distribution of scores in subjects with SLE, with higher scores indicating worse anxiety. Those with worse anxiety performed more poorly on RMCPT and SP compared with those without anxiety.
§Subjects reported their computer experience as either some, moderate or extensive experience; those with some or moderate computer experience performed worse on NSM and SM compared with those with extensive experience.
KA, kynurenic acid; QA, quinolinic acid.