Precision in Diagnosing and Classifying COPD: Comparison of Historical Height with Current Height and Arm Span to Predict FEV(1)

Are we neglecting long-term effects of vertebral shortening on pulmonary function in spinal tuberculosis?

PURPOSE

In developing part of the world, it is common to see complete destruction of vertebral bodies in tuberculosis. Our study aims to assess the effect of spinal tuberculosis with vertebral shortening on pulmonary function.

METHODS

Fifty cases of spinal TB (14 males, 36 females) managed both operatively and non-operatively, who presented to tertiary care institute between years 2011 and 2016 were assessed. Vertebral height loss was assessed by spinal deformity index (SDI). All patients underwent pulmonary function testing using same equipment sitting in upright position.

RESULTS

Mean age was 27.9 years (27.9 ± 11.9). 11 patients with mean SDI of 2.7 ± 1.1 showed normal lung function. 36 patients showed restrictive pattern of which 12 were mild, 14 were moderate and 10 showed severe pattern with a mean SDI of 3.8 ± 1.2, 5.6 ± 1.3 and 6.1 ± 1.4, respectively. 3 cases showed obstructive pattern. As the apex of curve shifted proximally, FVC% reduced. Increase in SDI value was associated with a fall in the vital capacity and FEV₁. Increase in the kyphotic angle was associated with a deleterious effect on PFT results.

CONCLUSIONS

Risk stratification of pulmonary dysfunction resulting from vertebral body height loss due to kyphosis will emphasize the need for early detection of spinal tuberculosis before deformity occurs.

ARTP statement on pulmonary function testing 2020

The Association for Respiratory Technology & Physiology (ARTP) last produced a statement on the performance of lung function testing in 1994. At that time the focus was on a practical statement for people working in lung function laboratories. Since that time there have been many technological advances and alterations to best practice in the measurement and interpretation of lung function assessments. In light of these advances an update was warranted. ARTP, therefore, have provided within this document, where available, the most up-to-date and evidence-based recommendations for the most common lung function assessments performed in laboratories across the UK. These recommendations set out the requirements and considerations that need to be made in terms of environmental and patient factors that may influence both the performance and interpretation of lung function tests. They also incorporate procedures to ensure quality assured diagnostic investigations that include those associated with equipment, the healthcare professional conducting the assessments and the results achieved by the subject. Each section aims to outline the common parameters provided for each investigation, a brief principle behind the measurements (where applicable), and suggested acceptability and reproducibility criteria.

Prediction models for pulmonary function during acute exacerbation of chronic obstructive pulmonary disease

OBJECTIVE

The pulmonary function test is an effort-dependent test; however, during acute exacerbation of chronic obstructive pulmonary disease (AECOPD), patients are unable to effectively cooperate due to poor health. The present study aimed to establish prediction models that only require demographic and inflammatory parameters to predict pulmonary function indexes: forced expiratory volume in one second (FEV₁) and forced vital capacity (FVC).

APPROACH

The goal was to establish prediction models based on multi-output support vector regression. A total of 143 subjects received a peripheral blood examination and pulmonary function test. The demographic and inflammatory parameters were used as input features, and FEV₁ and FVC were used as the target features in prediction models. Three models (mixed model, severe model and nonsevere model) were established with FEV₁ < 1 l as the threshold of severe episodes of AECOPD. The values of FEV₁ and FVC from the pulmonary function tests were compared with the prediction models to validate the performances of the developed prediction models.

MAIN RESULTS

The severe and nonsevere models' prediction performances were better than that of the mixed model. The mean squared errors were lower than 0.05 l², and the decision coefficients (R ²) were higher than 0.40. The two-tailed t-test results showed that for both severe and nonsevere models, the absolute percentage errors of FEV₁ and FVC were within 10%.

SIGNIFICANCE

Our study shows the feasibility of predicting the pulmonary function indexes FEV₁ and FVC with demographic and inflammatory parameters when the pulmonary function test fails to be implemented, which is beneficial for the treatment of AECOPD.

Relationship Between Vertebral Fracture Burden, Height Loss, and Pulmonary Function in Postmenopausal Women With Osteoporosis

The purpose of this analysis was to assess the association of osteoporosis-related vertebral fracture burden and pulmonary function. This study also examined the relationship between vertebral fracture burden and height loss, estimated by arm span - height. This was a single-site and single-visit study. Patients had a history of at least 1 moderate or severe vertebral fracture. Vertebral fracture burden was quantified using the spinal deformity index (SDI). Pulmonary function during inspiration was determined by spirometry. Forty-one women aged 70-91 completed the study. Vertebral fracture burden negatively correlated with forced inspiratory vital capacity and inspiratory time. For each unit increase in SDI, forced inspiratory vital capacity decreased by 1.62%, and inspiratory time decreased by 2.39%. There was no correlation between SDI and measures of inspiratory flow. For each unit increase in SDI, height decreased by about 0.5 cm. Vertebral fractures were associated with decreased lung volume and height loss.

Impact of direct substitution of arm span length for current standing height in elderly COPD

Background

Arm span length is related to standing height and has been studied as a substitute for current standing height for predicting lung function parameters. However, it has never been studied in elderly COPD patients.

Purpose

To evaluate the accuracy of substituting arm span length for current standing height in the evaluation of pulmonary function parameters and severity classification in elderly Thai COPD patients.

Materials and methods: Current standing height and arm span length were measured in COPD patients aged >60 years. Postbronchodilator spirometric parameters, forced vital capacity (FVC), forced expiratory volume in first second (FEV₁), and ratio of FEV₁/FVC (FEV₁%), were used to classify disease severity according to global initiative for chronic obstructive lung disease criteria. Predicted values for each parameter were also calculated separately utilizing current standing height or arm span length measurements. Student’s t-tests and chi-squared tests were used to compare differences between the groups. Statistical significance was set at P<0.05.

Results

A total of 106 COPD patients with a mean age of 72.1±7.8 years, mean body mass index of 20.6±3.8 kg/m², and mean standing height of 156.4±8.3 cm were enrolled. The mean arm span length exceeded mean standing height by 7.7±4.6 cm (164.0±9.0 vs 156.4±8.3 cm, P<0.001), at a ratio of 1.05±0.03. Percentages of both predicted FVC and FEV₁ values based on arm span length were significantly lower than those using current standing height (76.6±25.4 vs 61.6±16.8, P<0.001 and 50.8±25.4 vs 41.1±15.3, P<0.001). Disease severity increased in 39.6% (42/106) of subjects using arm span length over current standing height for predicted lung function.

Conclusion

Direct substitution of arm span length for current standing height in elderly Thai COPD patients should not be recommended in cases where arm span length exceeds standing height by more than 4 cm.

Best lung function equations for the very elderly selected by survival analysis

We evaluated which equations best predicted the lung function of a cohort of nonagenarians based on which best accounted for subsequent survival. In 1998, we measured lung function, grip strength and dementia score (Mini Mental State Examination (MMSE)) in a population-based sample of 2262 Danes born in 1905. Mortality was registered to 2011 when only five (0.2%) subjects were alive. In half the cohort, we recorded forced expiratory volume in 1 s (FEV1). Complete data were available in 592 subjects with results expressed as standardised residuals (SR) using various prediction equations. Cox proportional hazard regression found lower FEV1SR was a predictor of mortality having controlled for MMSE, grip strength and sex. The US National Health and Nutrition Examination Survey (NHANES) III (1999) equations gave a better spread of median survival by FEV1SR quartile: 3.94, 3.65, 3.51 and 2.61 years with a hazard ratio for death of 1, 1.16, 1.32 and 1.60 respectively, compared with equations derived with the inclusion of elderly subjects. We conclude that extrapolating from NHANES III equations to predict lung function in nonagenarians gave better survival predictions from spirometry than when employing equations derived using very elderly subjects with possible selection bias. These findings can help inform how future lung function equations for the elderly are derived.