Anthropometric and pulmonary function test profiles of outpatients with stable chronic obstructive pulmonary disease

The influence of 6 months of oral anabolic steroids on body mass and respiratory muscles in undernourished COPD patients

STUDY OBJECTIVE

To evaluate the influence of oral anabolic steroids on body mass index (BMI), lean body mass, anthropometric measures, respiratory muscle strength, and functional exercise capacity among subjects with COPD.

DESIGN

Prospective, randomized, controlled, double-blind study.

SETTING

Pulmonary rehabilitation program.

PARTICIPANTS

Twenty-three undernourished male COPD patients in whom BMI was below 20 kg/m2 and the maximal inspiratory pressure (PImax) was below 60% of the predicted value.

INTERVENTION

The study group received 250 mg of testosterone i.m. at baseline and 12 mg of oral stanozolol a day for 27 weeks, during which time the control group received placebo. Both groups participated in inspiratory muscle exercises during weeks 9 to 27 and cycle ergometer exercises during weeks 18 to 27.

MEASUREMENTS AND RESULTS

Seventeen of 23 subjects completed the study. Weight increased in nine of 10 subjects who received anabolic steroids (mean, +1.8+/-0.5 kg; p<0.05), whereas the control group lost weight (-0.4+/-0.2 kg). The study group's increase in BMI differed significantly from that of the control group from weeks 3 to 27 (p<0.05). Lean body mass increased in the study group at weeks 9 and 18 (p<0.05). Arm muscle circumference and thigh circumference also differed between groups (p<0.05). Changes in PImax (study group, 41%; control group, 20%) were not statistically significant. No changes in the 6-min walk distance or in maximal exercise capacity were identified in either group.

CONCLUSION

The administration of oral anabolic steroids for 27 weeks to malnourished male subjects with COPD was free of clinical or biochemical side effects. It was associated with increases in BMI, lean body mass, and anthropometric measures of arm and thigh circumference, with no significant changes in endurance exercise capacity.

Effect of reduced body weight on muscle aerobic capacity in patients with COPD

BACKGROUND

Reduced muscle aerobic capacity in COPD patients has been demonstrated in several laboratories by phosphorus magnetic resonance spectroscopy and by analysis of oxygen uptake (VO2) kinetics. COPD patients are usually elderly, hypoxemic, poorly active with muscle atrophy, and often malnourished. Under these conditions there is usually reduction of O2 delivery to the tissues (bulk O2 flow), redistribution of fiber type within the muscle, capillary rarefaction, and decreased mitochondrial function, alterations all capable of reducing muscle aerobic capacity. In COPD, the effect of reduced body mass on muscle aerobic capacity has not been investigated (to our knowledge).

METHODS

We studied 24 patients with stable COPD with moderate-to-severe airway obstruction (68+/-5 [SD] years; FEV1, 39+/-12% predicted; PaO2, 66+/-8 mm Hg; PaCO2, 41+/-3 mm Hg) with poor to normal nutritional status, as indicated by a low-normal percent of ideal body weight (IBW). Each subject first underwent 1-min maximal incremental cycle ergometer exercise for determination of VO2 peak and lactate threshold (LT). Subsequently, they performed a 10-min moderate (80% of LT-VO2) constant load exercise for determination of oxygen deficit (O2DEF) and mean response time VO2 (MRT). VO2, CO2 output (VCO2), and minute ventilation were measured breath by breath.

RESULTS

Patients displayed low VO2 peak (1,094+/-47 [SE] mL/min), LT-VO2 (35+/-3% predicted O2 max), and higher MRT-VO2 (67+/-4 s). Univariate regression analysis showed that percent of IBW correlated with indexes of maximal and submaximal aerobic capacity: vs VO2 peak, R=0.53 (p<0.01); vs MRT R=-0.77 (p<0.001). Using stepwise regression analysis, MRT correlated (R2=-0.70) with percent of IBW (p<0.01) and with PaO2 (p<0.05).

CONCLUSIONS

Reduced body mass has an independent negative effect on muscle aerobic capacity in COPD patients: this effect may explain the variability in exercise tolerance among patients with comparable ventilatory limitation.

COPD: overview of definitions, epidemiology, and factors influencing its development

COPD is a heterogeneous collection of conditions that can affect various structures within the lung in a number of different ways. These various processes can all result in limitation of expiratory airflow. If severe enough, this physiologic abnormality defines COPD. The various conditions that can lead to this syndrome are prevalent and often relentlessly progressive. In aggregate, they represent an important public health problem. This supplement outlines diagnostic and therapeutic strategies by which the practitioner can assist patients suffering from this condition.

Acute oxygen supplementation does not relieve the impairment of respiratory muscle strength in hypoxemic COPD

STUDY OBJECTIVES

To verify whether hypoxemia affects respiratory muscle strength in the absence of malnutrition and whether such effect, if present, is reversible with an acute oxygen supplementation.

DESIGN

Case series analysis, before-after trial.

SETTING

Outpatient pneumology departments of two university hospitals.

PATIENTS

One hundred twenty patients affected by COPD in stable conditions having actual to ideal body weight ratio of > or =90%.

MEASUREMENTS AND RESULTS

Maximal inspiratory pressure (MIP) was measured at functional residual capacity level in the whole sample of subjects and during oxygen supplementation in 58 patients having a PaO2< or =60 mm Hg when breathing in room air. Predictors of MIP were assessed by a multivariate analysis. MIP values before and after oxygen supplementation were compared by a paired t test. MIP was independently correlated with FVC (p<0.001), PaO2 (p<0.01), and age (p<0.01). In the subgroup of hypoxemic patients, MIP values did not change significantly after oxygen supplementation (3.08+/-1.74 vs 3.03+/-1.91 kPa, t=0.43, not significant).

CONCLUSIONS

Hypoxemia is an important negative correlate of MIP even in well-nourished COPD patients. Its effect is not reversible with an acute oxygen supplementation.

Pulmonary function in obese subjects with a normal FEV1/FVC ratio

STUDY OBJECTIVE

To determine pulmonary function test (PFT) profile and respiratory muscle strength (RMS) of a group of obese individuals who did not have evidence of obstructive airway disease or other underlying diseases affecting their respiratory system.

DESIGN

Prospective, open.

SETTING

PFT laboratory, VA Medical Center.

PARTICIPANTS

Sixty-three consecutive obese (body mass index greater than 27.8 kg/m2) male subjects without overt obstructive airway disease (FEV1/FVC ratio greater than 80%).

MEASUREMENTS AND RESULTS

Standard PFTs and maximum static inspiratory (PImax) and expiratory (PEmax) mouth pressures were determined. RMS was calculated from the following formula: (PImax+PEmax):2. Two distinct groups were identified, those with normal maximum voluntary ventilation (MVV) (> 80% predicted) and those with low MVV. Both inspiratory and expiratory flow rates (FVC, FEV1, forced expiratory flow at 50% vital capacity [V50], maximum inspiratory flow rate [MIFR]), lung volumes (vital capacity [VC], inspiratory capacity [IC], expiratory reserve volume), PImax, and RMS were significantly lower, and residual volume/total lung capacity (RV/TLC) ratio was significantly higher in obese subjects with low MVV compared with those in whom MVV was normal. MVV correlated significantly with FVC, FEV1, V50, MIFR, TLC, VC, IC, RV/TLC, and RMS; the strongest correlation was with MIFR (r = 0.76, p < 0.0001).

CONCLUSIONS

Standard PFTs allow recognition of a subgroup of obese subjects without overt obstructive airway disease who have more severe lung dysfunction, the marker of which is a low MVV. Peripheral airway abnormalities may be responsible for these observations.

Undernutrition in rheumatoid arthritis patients with disability

Clinical evaluation of nutritional status (NS) was performed in 75 rheumatoid arthritis patients. They were distributed according to functional class, radiological stage and other prognostic factors (rheumatoid factor, extraarticular disease, disease duration). Evaluation of the different anthropometrical measurements in this group of long-standing RA patients (average disease duration: 10 years) revealed a significant impairment of lean body mass (LBM), especially among those with greater disability (Functional Class III and IV). Patients in more severe radiological stages (Radiological Stage III and IV) or patients with extraarticular disease also presented a significant loss of LBM compared with a matched cohort of the general population and patients with a more benign-course disease. There was less impairment of the fat mass, according to our clinical evaluation. Serological parameters of undernutrition (albumin and transferrin) did not show significant differences among the groups of patients. Clinical evaluation of NS in RA patients is a useful procedure for recognising patients at high risk of related complications by means of their poor nutritional status.

Nutritional state and exercise tolerance in patients with COPD

We hypothesized that in patients with COPD, poor nutritional status adversely influences exercise tolerance by limiting aerobic capacity of exercising muscles. In 28 patients with stable COPD, we correlated nutritional status with gas exchange indexes obtained during maximal incremental cycle ergometer exercise and with respiratory function parameters. On the basis of percent of ideal body weight (%IBW), patients were divided into three groups (GP): GP1 (n = 8, %IBW < 90); GP2 (n = 13, %IBW > or = 90 < 110); and GP3 (n = 7, %IBW > or = 110). When compared with normally nourished individuals (GPs 2 and 3), malnourished GP1 patients showed greater reduction in maximal workload and in peak O2 uptake (VO2 peak), with earlier onset of metabolic acidosis (anaerobic threshold [AT]); in addition, indexes reflecting O2 cost of ventilation were higher in GP1. Nutritional status could be correlated with exercise tolerance (VO2 peak, r = 0.82, p < 0.0001), with onset of metabolic acidosis (AT, r = 0.69, p < 0.0001) and with dead space/tidal volume ratio (VD/VT, r = -0.59, p < 0.001). Body weight was inversely correlated with indexes that are likely to reflect the increase in O2 cost of ventilation. We conclude that in patients with stable COPD, (1) malnutrition significantly affects muscle aerobic capacity and exercise tolerance, and (2) high wasted ventilation and O2 cost of ventilation may be responsible for the weight loss.

[Artificial nutrition in patients with chronic respiratory insufficiency undergoing surgery]

Denutrition is a common finding in patients with chronic respiratory failure (CRF). Preoperative denutrition increases the risk of nosocomial pneumonia and difficulties in weaning from mechanical ventilation. A preoperative nutritional support may have beneficial effects on respiratory muscles performance. However, prospective studies need to be carried out in patients with CRF to substantiate this hypothesis. Postoperative nutritional support is indicated if weaning from the ventilator is expected to require more than several days, in order to preserve the diaphragmatic function. Lipid-enriched nutrition may have a beneficial effect, when energy supply is high, as the resulting decrease in CO2 production may facilitate the weaning from the ventilator. A beneficial effect of branched-chain amino acid-enriched solutions has not been demonstrated in patients with CRF.