C-reactive protein alterations in bipolar disorder: a meta-analysis.
OBJECTIVE
There is growing evidence that bipolar disorder (BD) is associated with inflammation, including abnormal levels of acute-phase C-reactive protein (CRP). Our meta-analysis was conducted to estimate the size of the association between CRP levels and BD, accounting also for subgroup differences (mood phases and treatment).


METHODS
MEDLINE, EMBASE, PsycINFO, and ISI Web of Science and references of identified articles were searched up to June 2013 using the keywords (bipolar disorder) AND (C-reactive protein OR CRP).


METHODS
English language studies measuring blood levels of CRP in patients with BD and control subjects were selected, 136 abstracts were reviewed, 20 articles retrieved, and 11 studies included.


METHODS
Two independent reviewers extracted data. All studies were included in the primary analyses, and between-group differences for subanalyses were also reported. This meta-analysis was performed using random-effects models.


RESULTS
Eleven studies comprising 1,618 subjects were eligible for inclusion. Overall, CRP levels were significantly elevated in patients with BD versus controls (standardized mean difference [SMD] = 0.39; 95% CI, 0.24 to 0.55; P < .0001). CRP levels were significantly higher in manic (SMD = 0.73; 95% CI, 0.44 to 1.02; P < .001) and euthymic (SMD = 0.26; 95% CI, 0.01 to 0.51; P = .04), but not in depressed (SMD = 0.28; 95% CI, -0.17 to 0.73; P = .22) patients with BD compared to controls. CRP levels were unrelated to use of lithium or antipsychotic medication.


CONCLUSIONS
This meta-analysis supports an association between increased CRP levels and BD. Given that an elevated level of CRP is a marker of low-grade inflammation and a risk factor for cardiovascular and malignant diseases, measurement of CRP level might be relevant to the clinical care of bipolar patients.
Hôpital A. Chenevier, Pavillon Hartmann, 40, rue de Mesly, F-94000, Créteil, France aroldodargel@gmail.com.
Aroldo A
AA
Dargél
Ophelia
O
Godin
Flávio
F
Kapczinski
David J
DJ
Kupfer
Marion
M
Leboyer
D000339:Affect / Q000502:physiology; D015415:Biomarkers / Q000097:blood; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D002097:C-Reactive Protein / Q000378:metabolism*; D006801:Humans; D011237:Predictive Value of Tests
D015415:Biomarkers; D002097:C-Reactive Protein