Osteoarthritis in the UK Armed Forces: a review of its impact, treatment and future research

Within the UK Armed Forces, musculoskeletal injuries account for over half of all medical downgrades and discharges. Data from other Armed Forces show that osteoarthritis (OA), more common in military personnel, is likely to contribute to this, both in its primary form and following injury (post-traumatic OA, PTOA), which typically presents in the third or fourth decade. OA is not a progressive 'wear and tear' disease, as previously thought, but a heterogenous condition with multiple aetiologies and modulators, including joint damage, abnormal morphology, altered biomechanics, genetics, low-grade inflammation and dysregulated metabolism. Currently, clinical diagnosis, based on symptomatic or radiological criteria, is followed by supportive measures, including education, exercise, analgesia, potentially surgical intervention, with a particular focus on exercise rehabilitation within the UK military. Developments in OA have led to a new paradigm of organ failure, with an emphasis on early diagnosis and risk stratification, prevention strategies (primary, secondary and tertiary) and improved aetiological classification using genotypes and phenotypes to guide management, with the introduction of biological markers (biomarkers) potentially having a role in all these areas. In the UK Armed Forces, there are multiple research studies focused on OA risk factors, epidemiology, biomarkers and effectiveness of different interventions. This review aims to highlight OA, especially PTOA, as an important diagnosis to consider in serving personnel, outline current and future management options, and detail current research trends within the Defence Medical Services.

Baseline self-report 'central mechanisms' trait predicts persistent knee pain in the Knee Pain in the Community (KPIC) cohort

OBJECTIVES

We investigated whether baseline scores for a self-report trait linked to central mechanisms predict 1 year pain outcomes in the Knee Pain in the Community cohort.

METHOD

1471 participants reported knee pain at baseline and responded to a 1-year follow-up questionnaire, of whom 204 underwent pressure pain detection thresholds (PPTs) and radiographic assessment at baseline. Logistic and linear regression models estimated the relative risks (RRs) and associations (β) between self-report traits, PPTs and pain outcomes. Discriminative performance for each predictor was compared using receiver-operator characteristics (ROC) curves.

RESULTS

Baseline Central Mechanisms trait scores predicted pain persistence (Relative Risk, RR = 2.10, P = 0.001) and persistent pain severity (β = 0.47, P < 0.001), even after adjustment for age, sex, BMI, radiographic scores and symptom duration. Baseline joint-line PPTs also associated with pain persistence (RR range = 0.65 to 0.68, P < 0.02), but only in univariate models. Lower baseline medial joint-line PPT was associated with persistent pain severity (β = -0.29, P = 0.013) in a fully adjusted model. The Central Mechanisms trait model showed good discrimination of pain persistence cases from resolved pain cases (Area Under the Curve, AUC = 0.70). The discrimination power of other predictors (PPTs (AUC range = 0.51 to 0.59), radiographic OA (AUC = 0.62), age, sex and BMI (AUC range = 0.51 to 0.64), improved significantly (P < 0.05) when the central mechanisms trait was included in each logistic regression model (AUC range = 0.69 to 0.74).

CONCLUSION

A simple summary self-report Central Mechanisms trait score may indicate a contribution of central mechanisms to poor knee pain prognosis.

The relative efficacy of topical non-steroidal anti-inflammatory drugs and capsaicin in osteoarthritis: a network meta-analysis of randomised controlled trials

OBJECTIVE

To compare the efficacy of topical non-steroidal anti-inflammatory drugs (NSAIDs) with topical capsaicin for pain relief in osteoarthritis (OA).

DESIGN

A systematic literature search was conducted for randomised controlled trials (RCTs) examining any topical NSAID or capsaicin in OA. Pain relief at or nearest to 4 weeks was pooled using a random-effects network meta-analysis (NMA) in a Frequentist and Bayesian setting. Analysis was conducted for all trials and for trials using drugs listed as licensed for OA in the British National Formulary (BNF).

RESULTS

The trial network comprised 28 RCTs (7372 participants), of which 17 RCTs (3174 participants) were included in the as licensed analyses. No RCTs directly compared topical NSAIDs with capsaicin. Placebo was the only common comparator for topical NSAIDs and capsaicin. Frequentist and Bayesian effect size (ES) estimates were in agreement. Topical NSAIDs were statistically superior to placebo overall (ES 0.30, 95% confidence interval [CI] 0.19 to 0.41) and as licensed (ES 0.32, 95% CI 0.24 to 0.39). However, capsaicin was only statistically superior to placebo when used at licensed doses (ES 0.41, 95% CI 0.17 to 0.64). No significant differences were observed in pain relief between topical NSAIDs and capsaicin (overall: ES 0.04, 95% CI -0.26 to 0.33; as licensed: ES-0.09, 95% CI -0.34 to 0.16).

CONCLUSIONS

Current evidence indicates that topical NSAIDs and capsaicin in licensed doses may be equally effective for pain relief in OA. Whether the equivalence varies between individuals remains unknown.

Metabolism of Sodium Pentosan Polysulphate in Man Measured by a New Competitive Binding Assay for Sulphated Polysaccharides – Comparison with Effects Upon Anticoagulant Activity, Lipolysis and Platelet α-Granule Proteins

Three human volunteers were injected with a range of doses of pentosan polysulphate, SP54, i.v. or s.c. A competitive binding assay (CBA) for sulphated polysaccharides was used to detect circulating SP54 after doses as low as 1 mg i.v. and a linear relationship was observed between the peak plasma concentration of SP54 measured by CBA and the administered dose. A comparison was made between the clearance of SP54 measured by CBA and its anticoagulant and lipolytic activities. SP54 was detectable by CBA after doses which caused no alteration in activated partial thromboplastin time (APTT) or anti-factor Xa activity but after which a small increase of lipase activity was measurable. After SP54 at 10 mg i.v. or 100 mg s.c. anti-factor Xa activity was 4-6 times greater than would be expected from the in vitro activity of the concentrations of SP54 measured by CBA. Like heparin and other heparin analogues, SP54 caused an increase in plasma concentrations of platelet factor 4 (PF4) without a concomitant rise in p-thromboglobulin (β-TG).

It is concluded that the newly developed CBA will provide a more sensitive means than conventional bioassays for the determination of plasma concentrations of SP54.

Interpretation of pediatric lung function: impact of ethnicity

RATIONALE

To evaluate the appropriateness of spirometric and plethysmographic reference equations in healthy young children according to ethnic origin.

METHODS

Spirometry data were collated in 400 healthy children (214 Black and 186 White) aged 6-12 years. Of these children, 68 Black and 115 White children also undertook plethysmography. Results were expressed as percent predicted according to commonly used equations for spirometry and plethysmography.

RESULTS

Black children had lower lung function for a given height compared to White children. The magnitude and direction of these differences varied according to specific outcome. In the studied age range (6-12 years) the ethnic-specific Wang equations were adequate for spirometry (mean results approximating 100% predicted in both ethnic groups). By contrast, significant differences were found between observed and % predicted plethysmographic lung volumes according to published equations derived from White children: Among the Black children, function residual capacity (FRC) and total lung capacity (TLC) were on average, 14 and 6% lower than predicted, whereas mean residual volume (RV) and RV/TLC were 4 and 10% higher. Among White children, the Rosenthal equations gave the best fit, with the exception of FRC which was, on average, 9% lower than predicted.

CONCLUSION

Spirometry equations may suffice in Black children; however, interpretation of static lung volumes in Black children is limited due to inappropriate reference equations. More appropriate plethysmographic reference equations that are applicable to all ethnic groups across the entire age range are urgently needed.

Increasing adherence with the use of hip protectors for older people living in the community

For people at high risk of hip fracture living in community settings, providing hip protectors at no cost increased adherence, but the additional effect of an educational programme was limited. Overall, the level of adherence was modest.

INTRODUCTION

The objective of the study was to increase adherence with hip protector use by older people at high risk of hip fracture. The study included two randomised controlled trials with 308 older people recruited from three hospital rehabilitation wards and 171 older people recruited from the community.

METHODS

Participants were randomised into three groups. The control group received a brochure about hip protectors. The no cost group were fitted with free hip protectors and asked to use them. The combined group received free hip protectors and education sessions about their use. Adherence with the use of hip protectors at 3 and 6 months after recruitment was measured. Secondary outcomes were falls, fractures and hospitalisations.

RESULTS

Very few participants in the two control groups bought a hip protector. Overall adherence in the four intervention groups was modest, but higher in the community recruitment setting (49%) than in the hospital recruitment setting (36%) at 6 months. In the community recruitment group, at 3 months of follow-up, a significantly higher number of participants in the combined group (62%) were wearing hip protectors compared to the no cost group (43%, p=0.04). Five hip fractures occurred during the study, with four sustained whilst not wearing the hip protectors.

CONCLUSION

Providing hip protectors at no cost to community living older people at high risk of hip fractures modestly increases initial acceptance and adherence with hip protector use. Additional education may further increase hip protector use in people living in the community in the short term.

Reference values for lung function: past, present and future

Reliable interpretation of pulmonary function results relies on the availability of appropriate reference data to help distinguish between health and disease and to assess the severity and nature of any functional impairment. The overwhelming number of published reference equations, with at least 15 published for spirometry alone in the past 3 yrs, complicates the selection of an appropriate reference. The use of inappropriate reference equations and misinterpretation, even when potentially appropriate equations are used, can lead to serious errors in both under and over diagnosis, with its associated burden in terms of financial and human costs. Further misdiagnosis occurs when fixed cut-offs, such as 80% predicted forced expiratory volume in 1 s (FEV(1)) or 0.70 FEV(1)/forced vital capacity, are used; particularly in young children and elderly adults. While per cent predicted has historically been used to interpret lung function results, z-scores are more appropriate as they take into account the predicted value, as well as the between-subject variability of measurements. We aim to highlight some of the main issues in selecting and using reference equations and discuss how recent developments may improve interpretation of pulmonary function results.

Nature and severity of lung function abnormalities in extremely pre-term children at 11 years of age

Advances in neonatal care have resulted in increased survival of children born extremely pre-term (EP). Nevertheless the incidence of bronchopulmonary dysplasia and long-term respiratory morbidity remains high. We investigated the nature of pathophysiological changes at 11 yrs of age to ascertain whether respiratory morbidity in EP children primarily reflects alterations in the lung periphery or more centralised airway function in this population. Spirometry, plethysmography, diffusing capacity, exhaled nitric oxide, multiple-breath washout, skin tests and methacholine challenge were used during laboratory-based assessments in a subgroup of the 1995 EPICure cohort and in controls. Results were obtained in 49 EP and 52 control children. Lung function abnormalities were found in 78% of EP children, with evidence of airway obstruction, ventilation inhomogeneity, gas trapping and airway hyperresponsiveness. Levels of atopy and exhaled nitric oxide were similar between the groups. Prior wheeze was associated with significant reductions in forced flows and volumes. By contrast, abnormalities of the lung periphery appear to be mediated primarily through EP birth per se. The prevalence of lung function abnormalities, which is largely obstructive in nature and likely to have long-term implications, remains high among 11-yr-old children born EP. Spirometry proved an effective means of detecting these persistent abnormalities.

Influence of secular trends and sample size on reference equations for lung function tests

The aim of our study was to determine the contribution of secular trends and sample size to lung function reference equations, and establish the number of local subjects required to validate published reference values. 30 spirometry datasets collected between 1978 and 2009 provided data on healthy, white subjects: 19,291 males and 23,741 females aged 2.5-95 yrs. The best fit for forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC) and FEV(1)/FVC as functions of age, height and sex were derived from the entire dataset using GAMLSS. Mean z-scores were calculated for individual datasets to determine inter-centre differences. This was repeated by subdividing one large dataset (3,683 males and 4,759 females) into 36 smaller subsets (comprising 18-227 individuals) to preclude differences due to population/technique. No secular trends were observed and differences between datasets comprising >1,000 subjects were small (maximum difference in FEV(1) and FVC from overall mean: 0.30- -0.22 z-scores). Subdividing one large dataset into smaller subsets reproduced the above sample size-related differences and revealed that at least 150 males and 150 females would be necessary to validate reference values to avoid spurious differences due to sampling error. Use of local controls to validate reference equations will rarely be practical due to the numbers required. Reference equations derived from large or collated datasets are recommended.

Effect of chest wall vibration timing on peak expiratory flow and inspiratory pressure in a mechanically ventilated lung model

OBJECTIVE

To investigate the effects of chest wall vibration timing on air flow and pressure in a ventilated lung model.

DESIGN

Laboratory-based bench study.

PARTICIPANTS

Thirty physiotherapists with experience in intensive care.

INTERVENTION

Physiotherapists applied three sets of eight chest wall vibrations to an intubated, mechanically ventilated mannequin. Vibrations were applied at the start of expiration (optimal), mid to late inspiration (early) and early to mid expiration (late). Air flow, peak pressure and volume were measured continuously. Forces applied during vibrations were recorded using a force-sensing mat, placed under the physiotherapists' hands.

RESULTS

During optimal and early vibrations, peak expiratory flow increased significantly compared with baseline ventilation [mean difference for optimal vibrations 8.8l/minute, 95% confidence interval (CI) 6.0 to 11.6; mean difference for early vibrations 7.0l/minute, 95% CI 4.3 to 9.9]. Late vibrations did not enhance expiratory flow. Peak inspiratory pressure was significantly higher during early vibrations compared with baseline values (mean difference 5.6cmH(2)O, 95% CI 2.9 to 8.2). Peak inspiratory pressure generated during early vibrations was, on average, 8.4cmH(2)O greater than with optimal timing.

CONCLUSION

The safety and effectiveness of respiratory physiotherapy treatments are likely to be influenced by the timing of vibrations within the breath cycle. Early vibrations generate potentially dangerous peak inspiratory pressures. Late vibrations, although not harmful, are not effective at increasing peak expiratory flow. This is an important consideration when training physiotherapists and evaluating outcomes of treatments in intensive care.

Reference equations for specific airway resistance in children: the Asthma UK initiative

Plethysmographic specific airway resistance (sR(aw)) is a useful research method for discriminating lung disease in young children. Its use in clinical management has, however, been limited by lack of consensus regarding equipment, methodology and reference data. The aim of our study was to collate reference data from healthy children (3-10 yrs), document methodological differences, explore the impact of these differences and construct reference equations from the collated dataset. Centres were approached to contribute sR(aw) data as part of the Asthma UK initiative. A random selection of pressure-flow plots were assessed for quality and site visits elucidated data collection and analysis protocols. Five centres contributed 2,872 measurements. Marked variation in methodology and analysis excluded two centres. sR(aw) over-read sheets were developed for quality control. Reference equations and recommendations for recording and reporting both specific effective and total airway resistance (sR(eff) and sR(tot), respectively) were developed for White European children from 1,908 measurements made under similar conditions. Reference sR(aw) data collected from a single centre may be misleading, as methodological differences exist between centres. These preliminary reference equations can only be applied under similar measurement conditions. Given the potential clinical usefulness of sR(aw), particularly with respect to sR(eff), methodological guidelines need to be established and used in prospective data collection.

Reference ranges for interrupter resistance technique: the Asthma UK Initiative

Measuring interrupter resistance (R(int)) is an increasingly popular lung function technique and especially suitable for preschool children because it is simple, quick and requires only passive cooperation. A European Respiratory Society (ERS)/American Thoracic Society (ATS) Task Force recently published empirical recommendations related to procedures, limitations and interpretation of the technique. However, for valid interpretation, high-quality reference equations are required and these have been lacking. The aim of the present study was to collate R(int) data from healthy children in order to produce more robust reference equations. A further aim was to examine the influence of methodological differences on predicted R(int) values. R(int) data from healthy children were collected from published and unpublished sources. Reference equations for expiratory and inspiratory R(int) were developed using the LMS (lambda, mu, sigma) method. Data from 1,090 children (51% males) aged 3-13 yrs were collated to construct sex-specific reference equations for expiratory R(int) and data from 629 children (51% males) were collated for inspiratory R(int). Height was the best independent predictor of both expiratory and inspiratory R(int). Differences between centres were clinically irrelevant, and differences between ethnic groups could not be examined. The availability of a large and generalisable sample and the use of modern statistical techniques enabled the development of more appropriate reference equations for R(int) in young children.

The Young Everest Study: effects of hypoxia at high altitude on cardiorespiratory function and general well-being in healthy children

OBJECTIVES

To assess the effect of altitude and acclimatisation on cardiorespiratory function and well-being in healthy children.

METHODS

A daily symptom diary, serial measurements of spirometry, end-tidal carbon dioxide (etCO(2)) and daytime and overnight pulse oximetry (SpO(2)), were undertaken at sea level and altitudes up to 3500 m in healthy children during a trekking holiday. SpO(2) at altitude was compared with that in flight and during acute hypoxic challenge (breathing 15% oxygen) at sea level.

RESULTS

Measurements were obtained in nine children aged 6-13 years (median 8). SpO(2) decreased significantly during the hypoxic challenge (difference -5%, 95% CI -6 to -3%, p<0.01) but remained above 90% in all children. There was a significant fall in daytime and overnight SpO(2) (95% CI -11.9 to -7.5% and -12 to -8, respectively) and etCO(2) (-8.5 to -4.5 mm Hg) as the children ascended to 3500 m. There was a significant increase in SpO(2) (95% CI 1.1 to 4.9%) and a further drop in etCO(2) (-5.9 to -0.8 mm Hg) after a week at altitude, etCO(2) being negatively correlated with SpO(2). There was no correlation between SpO(2) during hypoxic challenge, in flight or at altitude. Lung function remained within 7% of baseline in all but two children, in whom reductions of up to 23% in FVC and 16% FEV(1) were observed at altitude. The children generally remained well, but the Lake Louise scoring system was unreliable in this age group.

CONCLUSIONS

A wide range of physiological responses to altitude are evident in healthy children. This study should inform future larger studies in children to improve understanding of responses to hypoxia in health and disease.

Restriction enzyme analysis of the apolipoprotein A-I gene in fish eye disease and Tangier disease

Restriction enzyme analysis of the apolipoprotein A-I (apo A-I) gene was performed in two patients with fish eye disease and one with Tangier disease. Despite the marked deficiency of high density lipoprotein and concomitantly of apo A-I in these two conditions, no evidence was found for major deletions or insertions in the apo A-I gene.

Age- and size-related reference ranges: a case study of spirometry through childhood and adulthood

Age-related reference ranges are useful for assessing growth in children. The LMS method is a popular technique for constructing growth charts that model the age-changing distribution of the measurement in terms of the median, coefficient of variation and skewness. Here the methodology is extended to references that depend on body size as well as age, by exploiting the flexibility of the generalised additive models for location, scale and shape (GAMLSS) technique. GAMLSS offers general linear predictors for each moment parameter and a choice of error distributions, which can handle kurtosis as well as skewness. A key question with such references is the nature of the age-size adjustment, additive or multiplicative, which is explored by comparing the identity link and log link for the median predictor.There are several measurements whose reference ranges depend on both body size and age. As an example, models are developed here for the first four moments of the lung function variables forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC) and FEV(1)/FVC in terms of height and age, in a data set of 3598 children and adults aged 4 to 80 years. The results show a strong multiplicative association between spirometry, height and age, with a large and nonlinear age effect across the age range. Variability also depends nonlinearly on age and to a lesser extent on height. FEV(1) and FVC are close to normally distributed, while FEV(1)/FVC is appreciably skew to the left. GAMLSS is a powerful technique for the construction of such references, which should be useful in clinical medicine.

Association of prematurity, lung disease and body size with lung volume and ventilation inhomogeneity in unsedated neonates: a multicentre study

BACKGROUND

Previous studies have suggested that preterm birth with or without subsequent chronic lung disease is associated with reduced functional residual capacity (FRC) and increased ventilation inhomogeneity in the neonatal period. We aimed to establish whether such findings are associated with the degree of prematurity, neonatal respiratory illness and disproportionate somatic growth.

METHODS

Multiple breath washout measurements using an ultrasonic flowmeter were obtained from 219 infants on 306 test occasions during the first few months of life, at three neonatal units in the UK and Australia. Tests were performed during unsedated sleep in clinically stable infants (assigned to four exclusive diagnostic categories: term controls, preterm controls, respiratory distress syndrome and chronic lung disease). The determinants of neonatal lung function were assessed using multivariable, multilevel modelling.

RESULTS

After adjustment for age and body proportions, the factors gestation, intrauterine growth restriction and days of supplemental oxygen were all significantly associated with a reduced FRC. In contrast, increased ventilation inhomogeneity (elevated lung clearance index) was only significantly associated with duration of supplemental oxygen. After adjusting for continuous variables, diagnostic category made no further contribution to the models. Despite using identical techniques, unexpected inter-centre differences occurred, associated with the equipment used; these did not alter the negative association of preterm delivery and disease severity with lung function outcomes.

CONCLUSION

Reduction in FRC is independently associated with prematurity, intrauterine growth restriction and severity of neonatal lung disease. Determinants of lung function shortly after birth are highly complex in different disease groups.

The EPICure study: comparison of pediatric spirometry in community and laboratory settings

RATIONALE

Accuracy of spirometry testing is a prerequisite for its use as an objective outcome measure in large epidemiological studies. We compared spirometry measurements obtained by trained pediatricians in a variety of school settings with those obtained in the laboratory by respiratory physiologists.

METHODS

Following a 3-day training course, three pediatricians carried out spirometry in children born extremely preterm (EP) and age matched controls in schools across the UK and Ireland (The EPICure study). A subgroup had repeated measurements in the laboratory. Spirometric flows and volumes were expressed as Z-scores. Bland-Altman analysis was used to calculate within-subject differences.

RESULTS

Fifty children (40% boys), 37 (74%) of whom were born EP, with a mean age 10.8 years had paired spirometry results (average interval between tests: 20.3 weeks). There was no statistically significant difference between any of the outcome variables: mean (95% CI of difference) in Z-scores [school-laboratory]) being 0.0 (-0.1; 0.1) for FEV(1), 0.1 (-0.1; 0.3) for FVC, -0.1 (-0.3; 0.1) for FEF(25-75), and 0.0 (-0.3; 0.1) for FEV(1)/FVC. Within individuals, the 95% limits of agreement for repeated measures were within +/- 1 Z-score for FEV(1) and FVC, and within +/- 1.5 Z-score for FEF(25-75) and FEV(1)/FVC.

CONCLUSION

With appropriate training, quality control, and support, pediatric spirometry can reliably be performed outside the lung function laboratory.

Lung function and clinical risk factors for asthma in infants and young children with recurrent wheeze

BACKGROUND

Although several risk factors for asthma have been identified in infants and young children with recurrent wheeze, the relevance of assessing lung function in this group remains unclear. Whether lung function is reduced during the first 2 years in recurrently wheezy children, with and without clinical risk factors for developing subsequent asthma (ie, parental asthma, personal history of allergic rhinitis, wheezing without colds and/or eosinophil level >4%) compared with healthy controls was assessed in this study.

METHODS

Forced expiratory flows and volumes in steroid naïve young children with >or=3 episodes of physician confirmed wheeze and healthy controls, aged 8-20 months, were measured using the tidal and raised volume rapid thoracoabdominal compression manoeuvres.

RESULTS

Technically acceptable results were obtained in 50 wheezy children and 30 controls using tidal rapid thoracoabdominal compression, and 44 wheezy children and 29 controls with the raised volume technique. After adjustment for sex, age, body length at test and maternal smoking, significant reductions in z scores for forced expiratory volume at 0.5 s (mean difference (95% CI) -1.0 (-1.5 to -0.5)), forced expired flow after 75% forced vital capacity (FVC) has been exhaled (FEF(25)) (-0.6 (-1.0 to -0.2)) and average forced expired flow over the mid 50% of FVC (FEF(25-75)) (-0.8 (-1.2 to -0.4)) were observed in those with recurrent wheeze compared with controls. Wheezy children with risk factors for asthma (n = 15) had significantly lower z scores for FVC (-0.7 (-1.4 to -0.04)) and FEF(25-75) (-0.6 (-1.2 to -0.1)) than those without such risk factors (n = 29).

CONCLUSIONS

Compared with healthy controls, airway function is reduced in young children with recurrent wheeze, particularly those at risk for subsequent asthma. These findings provide further evidence for associations between clinical risk factors and impaired respiratory function in early life.

Using the lower limit of normal for the FEV1/FVC ratio reduces the misclassification of airway obstruction

AIM

The prevalence of airway obstruction varies widely with the definition used.

OBJECTIVES

To study differences in the prevalence of airway obstruction when applying four international guidelines to three population samples using four regression equations.

METHODS

We collected predicted values for forced expiratory volume in 1 s/forced vital capacity (FEV(1)/FVC) and its lower limit of normal (LLN) from the literature. FEV(1)/FVC from 40 646 adults (including 13 136 asymptomatic never smokers) aged 17-90+years were available from American, English and Dutch population based surveys. The prevalence of airway obstruction was determined by the LLN for FEV(1)/FVC, and by using the Global Initiative for Chronic Obstructive Lung Disease (GOLD), American Thoracic Society/European Respiratory Society (ATS/ERS) or British Thoracic Society (BTS) guidelines, initially in the healthy subgroup and then in the entire population.

RESULTS

The LLN for FEV(1)/FVC varied between prediction equations (57 available for men and 55 for women), and demonstrated marked negative age dependency. Median age at which the LLN fell below 0.70 in healthy subjects was 42 and 48 years in men and women, respectively. When applying the reference equations (Health Survey for England 1995-1996, National Health and Nutrition Examination Survey (NHANES) III, European Community for Coal and Steel (ECCS)/ERS and a Dutch population study) to the selected population samples, the prevalence of airway obstruction in healthy never smokers aged over 60 years varied for each guideline: 17-45% of men and 7-26% of women for GOLD; 0-18% of men and 0-16% of women for ATS/ERS; and 0-9% of men and 0-11% of women for BTS. GOLD guidelines caused false positive rates of up to 60% when applied to entire populations.

CONCLUSIONS

Airway obstruction should be defined by FEV(1)/FVC and FEV(1) being below the LLN using appropriate reference equations.

Wireless capsule endoscopy in the investigation of intestinal Behçet's syndrome

OBJECTIVE

Intestinal Behçet's Syndrome (BS) is a difficult diagnosis to establish. We describe the use of wireless capsule endoscopy (WCE) in the investigation of 11 patients with suspected intestinal BS.

METHODS

Out of 11 patients, 10 with suspected intestinal BS were found to have small intestinal ulcers on capsule endoscopy. Each case was retrospectively assessed for symptoms, signs, anaemia, other investigations, treatment and complications.

RESULTS

All 11 patients had established diagnoses of BS as defined by the International Study Group criteria. Central abdominal pain and change in bowel habit were the predominant symptoms, both occurring in seven patients. Upper gastrointestinal (GI) endoscopy and colonoscopy identified duodenitis, ileitis and colitis in three patients. Barium studies and CT were normal in all cases. WCE revealed small intestinal ulcers throughout the ileum in five patients and ulcers located either in the proximal and/or distal ileum in five other patients. One patient had significant symptoms, signs and ulcers leading to a change in treatment to infliximab, and this resulted in resolution of symptoms and ulcers. Ten age- and sex-matched controls investigated for unexplained GI symptoms had no intestinal lesions on capsule endoscopy.

CONCLUSION

WCE is useful in the investigation of GI symptoms in BS. It is particularly helpful in those patients in whom conventional investigations have been normal or fail to account for symptoms and signs. This technique may guide treatment and provide a better understanding of intestinal pathology in BS.