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The mediating role of cytokine IL-6 on the relationship of FEV₁ upon 6-minute walk distance in chronic obstructive pulmonary disease.

Baldi S, Jose PE, Bruschi C, Pinna GD, Maestri R, Rezzani A, Bellinzona E, Fracchia C, Dacosto E, Crotti P, Montemartini S - Int J Chron Obstruct Pulmon Dis (2014)

Bottom Line: Age functioned as a significant moderator of the mediational pattern.For individuals aged <70 years, the standardized indirect effect was significant (0.122, 95% confidence interval [CI]: 0.044-0.254, P=0.004), and for individuals >70 years it was not significant (0.04, 95% CI: -0.010 to 0.142, P=0.10).This moderated mediation result based on concurrent data suggests, but does not prove, a causal role of systemic inflammatory syndrome on progression from functional impairment to "frailty" status and substantial disability in aging chronic obstructive pulmonary disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation IRCCS, Montescano, Pavia, Italy.

ABSTRACT

Objectives: To explore the mediating role of protein interleukin-6 (IL-6) on the relationship between forced expiratory volume in 1 second (FEV1) and 6-minute walk distance (6MWD) and, further, to determine whether status variables (such as age, sex, and body mass index [BMI]) operate as moderators of this mediation relationship.

Design: Moderated mediation model.

Setting: An inpatient pulmonary rehabilitation center in Italy.

Participants: All 153 patients involved in the screening of a randomized controlled clinical trial (ClinicalTrials.gov identifier: NCT01253941) were included in this study. All patients were Global initiative for chronic Obstructive Lung Disease (GOLD) stages I-IV and were aged 70.1±9.1 years.

Measurements: At run-in phase of the protocol, clinical and functional screening included BMI, fasting plasma levels of protein (IL-6), spirometry, and standardized 6-minute walking test, measured at the start of the respiratory rehabilitation program.

Methods: The size of the indirect effect of the initial variable (FEV1) upon the outcome variable (6MWD) through the intervening variable (IL-6) was computed and tested for statistical significance. Moderated mediation analyses were subsequently conducted with age, sex, and BMI.

Results: FEV1 averaged 53.4%±21.2%, and 6MWD 66.4%±41.3% of predicted. Median protein IL-6 was 6.68 pg/mL (interquartile range: 5.96). A bootstrapped mediation test supported the predicted indirect pathway (P=0.003). The indirect effect through IL-6 log units accounted for 17% of the total effect between FEV1 and 6MWD. Age functioned as a significant moderator of the mediational pattern. For individuals aged <70 years, the standardized indirect effect was significant (0.122, 95% confidence interval [CI]: 0.044-0.254, P=0.004), and for individuals >70 years it was not significant (0.04, 95% CI: -0.010 to 0.142, P=0.10).

Conclusion: This moderated mediation result based on concurrent data suggests, but does not prove, a causal role of systemic inflammatory syndrome on progression from functional impairment to "frailty" status and substantial disability in aging chronic obstructive pulmonary disease.

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Related in: MedlinePlus

Frequency of comorbidities in 153 patients suffering from chronic obstructive pulmonary disease.
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f1-copd-9-1091: Frequency of comorbidities in 153 patients suffering from chronic obstructive pulmonary disease.

Mentions: Figure 1 shows comorbidity frequencies ranging from 4% to 75%. Dyslipidemia, systemic arterial hypertension, hyperglycemia, and chronic respiratory failure were the four most prevalent comorbidities. Almost all patients had one or more comorbidity with a median of 5 (IQR 3–8). Among COPD patients segregated by median age, the ratio of males to females increased with age: 53 males to 19 females in the group younger than 70 years, and 70 males to eleven females in the group over 70 years (χ2=3.97, P=0.046). The ratio of individuals manifesting high versus low levels of IL-6 (cutoff value =5.4 pg/mL) was 38:34 in the younger group and 56:25 in the older group (χ2=4.31, P=0.038). The self-care item of the EQ-5D questionnaire showed that more problems were reported with increasing age (χ2=7.19, P=0.028). On the other hand, health status (VAS score ≤50) did not significantly vary by age (P=0.47).


The mediating role of cytokine IL-6 on the relationship of FEV₁ upon 6-minute walk distance in chronic obstructive pulmonary disease.

Baldi S, Jose PE, Bruschi C, Pinna GD, Maestri R, Rezzani A, Bellinzona E, Fracchia C, Dacosto E, Crotti P, Montemartini S - Int J Chron Obstruct Pulmon Dis (2014)

Frequency of comorbidities in 153 patients suffering from chronic obstructive pulmonary disease.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4199845&req=5

f1-copd-9-1091: Frequency of comorbidities in 153 patients suffering from chronic obstructive pulmonary disease.
Mentions: Figure 1 shows comorbidity frequencies ranging from 4% to 75%. Dyslipidemia, systemic arterial hypertension, hyperglycemia, and chronic respiratory failure were the four most prevalent comorbidities. Almost all patients had one or more comorbidity with a median of 5 (IQR 3–8). Among COPD patients segregated by median age, the ratio of males to females increased with age: 53 males to 19 females in the group younger than 70 years, and 70 males to eleven females in the group over 70 years (χ2=3.97, P=0.046). The ratio of individuals manifesting high versus low levels of IL-6 (cutoff value =5.4 pg/mL) was 38:34 in the younger group and 56:25 in the older group (χ2=4.31, P=0.038). The self-care item of the EQ-5D questionnaire showed that more problems were reported with increasing age (χ2=7.19, P=0.028). On the other hand, health status (VAS score ≤50) did not significantly vary by age (P=0.47).

Bottom Line: Age functioned as a significant moderator of the mediational pattern.For individuals aged <70 years, the standardized indirect effect was significant (0.122, 95% confidence interval [CI]: 0.044-0.254, P=0.004), and for individuals >70 years it was not significant (0.04, 95% CI: -0.010 to 0.142, P=0.10).This moderated mediation result based on concurrent data suggests, but does not prove, a causal role of systemic inflammatory syndrome on progression from functional impairment to "frailty" status and substantial disability in aging chronic obstructive pulmonary disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation IRCCS, Montescano, Pavia, Italy.

ABSTRACT

Objectives: To explore the mediating role of protein interleukin-6 (IL-6) on the relationship between forced expiratory volume in 1 second (FEV1) and 6-minute walk distance (6MWD) and, further, to determine whether status variables (such as age, sex, and body mass index [BMI]) operate as moderators of this mediation relationship.

Design: Moderated mediation model.

Setting: An inpatient pulmonary rehabilitation center in Italy.

Participants: All 153 patients involved in the screening of a randomized controlled clinical trial (ClinicalTrials.gov identifier: NCT01253941) were included in this study. All patients were Global initiative for chronic Obstructive Lung Disease (GOLD) stages I-IV and were aged 70.1±9.1 years.

Measurements: At run-in phase of the protocol, clinical and functional screening included BMI, fasting plasma levels of protein (IL-6), spirometry, and standardized 6-minute walking test, measured at the start of the respiratory rehabilitation program.

Methods: The size of the indirect effect of the initial variable (FEV1) upon the outcome variable (6MWD) through the intervening variable (IL-6) was computed and tested for statistical significance. Moderated mediation analyses were subsequently conducted with age, sex, and BMI.

Results: FEV1 averaged 53.4%±21.2%, and 6MWD 66.4%±41.3% of predicted. Median protein IL-6 was 6.68 pg/mL (interquartile range: 5.96). A bootstrapped mediation test supported the predicted indirect pathway (P=0.003). The indirect effect through IL-6 log units accounted for 17% of the total effect between FEV1 and 6MWD. Age functioned as a significant moderator of the mediational pattern. For individuals aged <70 years, the standardized indirect effect was significant (0.122, 95% confidence interval [CI]: 0.044-0.254, P=0.004), and for individuals >70 years it was not significant (0.04, 95% CI: -0.010 to 0.142, P=0.10).

Conclusion: This moderated mediation result based on concurrent data suggests, but does not prove, a causal role of systemic inflammatory syndrome on progression from functional impairment to "frailty" status and substantial disability in aging chronic obstructive pulmonary disease.

Show MeSH
Related in: MedlinePlus