Panic disorder and incident coronary heart disease: a systematic review and meta-analysis protocol

The Impact of Psychological Functioning on Cardiovascular Disease

PURPOSE OF REVIEW

We report on recent findings pertaining to the relationship of both negative and positive indicators of psychological functioning with cardiovascular disease (CVD) and briefly describe possible mechanistic pathways to account for these relationships.

RECENT FINDINGS

A body of observational literature suggests that (1) depression is predictive of CVD and is a consequence of CVD; (2) anxiety is related to CVD but the precise nature of this relationship remains unclear; and (3) negative affectivity and Type D personality are constructs that combine aspects of negative psychological functioning that have shown relationships with CVD and are worthy of future investigation. Positive psychological constructs of meaning/purpose and optimism predict better cardiovascular outcomes and other positive psychological constructs have received promising, but limited, attention in the literature. Key remaining questions concern the magnitude and directionality of possible causal relationships as well as the mechanisms accounting for them.

Differences in cytokines between patients with generalised anxiety disorder and panic disorder

OBJECTIVE

The purpose of this study was to evaluate the differences among panic disorder (PD), generalised anxiety disorder (GAD) and controls in inflammatory cytokines. We also analysed the correlation between inflammatory cytokines and response to escitalopram in PD and GAD patients.

METHODS

Eighty-six patients with PD, 86 patients with GAD and 86 healthy controls were recruited for this study. All participants were, respectively, assessed for severity of anxiety and panic symptoms using the Hamilton Anxiety Rating Scale (HAMA) and the Panic Disorder Severity Scale (PDSS); all patients in the study were also assessed after 4 weeks of treatment. The serum levels of cytokines were measured using a flow fluorescence microsphere assay.

RESULTS

Both PD and GAD patients had higher serum levels of interleukin 6 (IL-6) than controls, and patients with PD showed significantly higher IL-6 than GAD patients. Significant positive correlations were found between the IFN-γ levels and the severity of anxiety in GAD patients. Higher level of IL-6 was associated with better response to escitalopram treatment in PD patients. However, the baseline levels of cytokines were not associated with treatment responses in GAD patients.

CONCLUSION

The present findings suggest that patients with PD may have higher levels of IL-6 than GAD, and higher baseline levels of IL-6 may be a better response to escitalopram in the treatment of PD.

Heart rate variability changes in patients with panic disorder

BACKGROUND

This review aimed to evaluate whether patients with panic disorder (PD) exhibit different heart rate variability (HRV) compared to healthy controls and to determine whether HRV is different in patients with PD after treatment.

METHODS

Literature databases were searched for studies comparing resting-state HRV between drug-naïve patients with PD and healthy controls. Parameters from the short-term frequency-domain and long-term time domain were included.

RESULTS

In the low frequency (LF) analysis, no significant association was found between LF and PD (standardised mean difference [SMD] = -0.0443, 95% confidence interval [CI]: -0.1765 to 0.0879). In the high frequency (HF) analysis, no significant association was found between HF and PD (SMD = -0.1269, 95% CI: -0.2598 to 0.0059). In the LF/HF analysis, a significantly higher LF/HF ratio was found in cases than in controls, but the effect was moderate (SMD = 0.1390, 95% CI: 0.0180 to 0.2600). For the standard deviation of normal-to-normal intervals, a significantly lower value was observed in cases than in controls (SMD = -0.3133, 95% CI: -0.5459 to -0.0808).

LIMITATIONS

Limited sample size in the time-domain and treatment effect analyses.

CONCLUSIONS

Patients with PD had a higher short-term LF/HF ratio, indicating impaired sympathovagal balance. The LF/HF ratio findings were more consistent compared with LF and HF alone, making it a better parameter to interpret the LF and HF in conjunction. HRV may be a promising biomarker for predicting antidepressant response.

Mean Platelet Volume and Platelet Distribution Width Level in Patients with Panic Disorder

Background:

Changes in platelet indices have been reported in patients with panic disorder (PD). However, previous study findings are contradictory and inconclusive. The aim of this study was to evaluate and compare the platelet indices in patients with PD.

Materials and Methods:

Patients with PD (n = 123) and healthy controls (n = 133) were enrolled in this case control study. The platelet indices (mean platelet volume [MPV] and platelet distribution width [PDW]) along with red blood cell (RBC) indices (RBC count and red cell distribution width [RDW]) were compared between the two groups using the unpaired t-test.

Results:

Patients with PD had lower MPV (7.53 ± 0.93 fL vs. 8.91 ± 1.24 fL, P < 0.0001), higher PDW (16.96 ± 0.85 fL vs. 14.71 ± 2.07 fL, P < 0.0001), and higher platelet count (274.2 ± 80.66 × 10⁹ L⁻¹ vs. 243.1 ± 93.89 × 10⁹ L⁻¹, P < 0.005) than the healthy controls. Furthermore, there were significant differences between patients with PD and healthy controls in terms of their RBC count (4.32 ± 0.56 × 10¹² L⁻¹ vs. 4.08 ± 0.80 × 10¹² L⁻¹, P = 0.007) and RDW (16.48 ± 2.26 fL vs. 15.01 ± 2.25 fL, P < 0.0001).

Conclusion:

Patients with PD have increased PDW and RDW. The platelet and RBC indices may prove to be useful etiological and prognostic markers in patients with PD.

Panic disorder and incident coronary heart disease: a systematic review and meta-regression in 1131612 persons and 58111 cardiac events

BACKGROUND

Substantial healthcare resources are devoted to panic disorder (PD) and coronary heart disease (CHD); however, the association between these conditions remains controversial. Our objective was to conduct a systematic review of studies assessing the association between PD, related syndromes, and incident CHD.

METHOD

Relevant studies were retrieved from Medline, EMBASE, SCOPUS and PsycINFO without restrictions from inception to January 2015 supplemented with hand-searching. We included studies that reported hazard ratios (HR) or sufficient data to calculate the risk ratio and 95% confidence interval (CI) which were pooled using a random-effects model. Studies utilizing self-reported CHD were ineligible. Twelve studies were included comprising 1 131 612 persons and 58 111 incident CHD cases.

RESULTS

PD was associated with the primary incident CHD endpoint [adjusted HR (aHR) 1.47, 95% CI 1.24-1.74, p < 0.00001] even after excluding angina (aHR 1.49, 95% CI 1.22-1.81, p < 0.00001). High to moderate quality evidence suggested an association with incident major adverse cardiac events (MACE; aHR 1.40, 95% CI 1.16-1.69, p = 0.0004) and myocardial infarction (aHR 1.36, 95% CI 1.12-1.66, p = 0.002). The risk for CHD was significant after excluding depression (aHR 1.64, 95% CI 1.45-1.85) and after depression adjustment (aHR 1.38, 95% CI 1.03-1.87). Age, sex, length of follow-up, socioeconomic status and diabetes were sources of heterogeneity in the primary endpoint.

CONCLUSIONS

Meta-analysis showed that PD was independently associated with incident CHD, myocardial infarction and MACE; however, reverse causality cannot be ruled out and there was evidence of heterogeneity.