We thank Drs. Meade and Manolios for their thoughtful comments regarding the recent publication of our article. The points they raise are valid and important.
Our study examined the effect of glucocorticoids on cognitive function. Drs. Meade and Manolios drew attention to their findings that MTX also appears to have an effect on cognitive function (). Both our study and the study by Meade and Manolios suggest that medications for the treatment of RA may have an effect on cognition that, to date, has not been appreciated. Further research is clearly needed to elucidate this relationship and should be extended to examine the effects of biologic agents as well.
The second point Drs. Meade and Manolios raised is related to the assessment of cognitive function in RA, although their point could be extended to include other rheumatic conditions. As they point out, the rates of cognitive impairment found in individuals with RA have ranged from 9–31% (the latter estimate is from another of our articles) (). Multiple factors could contribute to this variation, including the assessment battery, mode of assessment, criteria for defining impairment, and characteristics of the sample. We chose to use a conservative definition of impairment because our sample was relatively highly educated, and the general view is that more highly educated individuals have greater cognitive reserves to protect against impairment. Age is also an important factor, which we acknowledged by using age-based norms in our determinations. Drs. Meade and Manolios suggested that other factors such as fatigue and comorbidities may also affect cognitive function, which is clearly true. However, whether these factors should be controlled for, as Drs. Meade and Manolios suggest, may depend on if they are viewed as part of the RA disease burden and thus contributors to the causation of cognitive impairment or are considered to be external to the disease. Regardless, the issue of cognitive impairment in RA, whether attributable to the disease itself, medications, or other factors, appears to need further study.
Again, we thank Drs. Meade and Manolios for their interest and comments and for drawing additional attention to the issues surrounding cognitive impairment and its assessment in RA.