Lynda Cochrane

The Thyroid Epidemiology, Audit, and Research Study (TEARS): Morbidity in Patients with Endogenous Subclinical Hyperthyroidism

OBJECTIVE Our objective was to investigate the long-term outcomes for patients with endogenous subclinical hyperthyroidism (SH). DESIGN Population record-linkage technology was used retrospectively to identify patients with SH and hospital admissions from January 1, 1993, to December 31, 2009. PATIENTS All Tayside residents over 18 yr old with at least two serum TSH measurements below the reference range for at least 4 months apart and normal free T(4)/total T(4) and normal total T(3) concentrations at baseline were included as potential cases. Using a unique patient identifier, data linkage enabled a cohort of SH cases to be identified from biochemistry, prescription, admission, and radioactive iodine treatment records matched to five comparators from the general population. OUTCOME MEASURES The association between endogenous SH and cardiovascular disease, fracture, dysrhythmia, dementia, and cancer was assessed. RESULTS Compared with the reference population, SH was associated with an increased risk of nonfatal cardiovascular morbidity, osteoporotic fracture, dysrhythmia, and dementia, with adjusted hazard ratios (HR) of 1.39 (1.22-1.58), 1.25 (1.04-1.50), 1.65 (1.26-2.17), and 1.64 (1.20-2.25), respectively. When SH patients who developed overt hyperthyroidism during follow-up were excluded, SH patients were associated with an increased risk of cardiovascular morbidity [HR = 1.36 (1.19-1.57)], dysrhythmia [HR = 1.39 (1.02-1.90)], and dementia [HR = 1.79 (1.28-2.51)] but not fracture and cancer. CONCLUSION Patients with endogenous SH have an increased risk of cardiovascular disease and dysrhythmia. There is an association with fracture and dementia that is not related to TSH concentration and therefore is less likely to be causally related. No association was found between SH and cancer.

The Thyroid Epidemiology, Audit, and Research Study (TEARS): the natural history of endogenous subclinical hyperthyroidism.

OBJECTIVE For patients with subclinical hyperthyroidism (SH), the objective of the study was to define the rates of progression to frank hyperthyroidism and normal thyroid function. DESIGN Record-linkage technology was used retrospectively to identify patients with SH in the general population of Tayside, Scotland, from January 1, 1993, to December 31, 2009. PATIENTS All Tayside residents with at least two measurements of TSH below the reference range for at least 4 months from baseline and normal free T(4)/total T(4) and total T(3) concentrations at baseline were included as potential cases. Using a unique patient identifier, data linkage enabled a cohort of SH cases to be identified from prescription, admission, and radioactive iodine treatment records. Cases younger than 18 yr of age were also excluded from the study. OUTCOME MEASURES The status of patients was investigated at 2, 5, and 7 yr after diagnosis. RESULTS We identified 2024 cases with SH, a prevalence of 0.63% and an incidence of 29 per 100,000 in 2008. Most SH cases without thyroid treatment remained as SH at 2 (81.8%), 5 (67.5%), and 7 yr (63.0%) after diagnosis. Few patients (0.5-0.7%) developed hyperthyroidism at 2, 5, and 7 yr. The percentage of SH cases reverting to normal increased with time: 17.2% (2 yr), 31.5% (5 yr), and 35.6% (7 yr), and this was more common in SH patients with baseline TSH between 0.1 and 0.4 mU/liter. CONCLUSION Very few SH patients develop frank hyperthyroidism, whereas a much larger proportion revert to normal, and many remain with SH.

Reduced Incidence of Lower-Extremity Amputations in People with Diabetes in Scotland: A nationwide study

OBJECTIVE To establish the incidence of nontraumatic lower-extremity amputation (LEA) in people with diabetes in Scotland. RESEARCH DESIGN AND METHODS This cohort study linked national morbidity records and diabetes datasets to establish the number of people with diabetes who underwent nontraumatic major and minor LEA in Scotland from 2004 to 2008. RESULTS Two thousand three hundred eighty-two individuals with diabetes underwent a nontraumatic LEA between 2004 and 2008; 57.1% (n = 1,359) underwent major LEAs. The incidence of any LEA among persons with diabetes fell over the 5-year study period by 29.8% (3.04 per 1,000 in 2004 to 2.13 per 1,000 in 2008, P < 0.001). Major LEA rates decreased by 40.7% from 1.87 per 1,000 in 2004 to 1.11 per 1,000 in 2008 (P < 0.001). CONCLUSIONS There has been a significant reduction in the incidence of LEA in persons with diabetes in Scotland between 2004 and 2008, principally explained by a reduction in major amputation.

Do you get value for money when you buy an expensive pair of running shoes

Objective: This investigation aims to determine if more expensive running shoes provide better cushioning of plantar pressure and are more comfortable than low-cost alternatives from the same brand. Methods: Three pairs of running shoes were purchased from three different manufacturers at three different price ranges: low (£40–45), medium (£60–65) and high (£70–75). Plantar pressure was recorded with the Pedar® in-shoe pressure measurement system. Comfort was assessed with a 100 mm visual analogue scale. A follow-on study was conducted to ascertain if shoe cushioning and comfort were comparable to walking while running on a treadmill. Forty-three and 9 male subjects participated in the main and follow-on studies, respectively. The main outcome measure was the evaluation of plantar pressure and comfort. Results: Plantar pressure measurements were recorded from under the heel, across the forefoot and under the great toe. Differences in plantar pressure were recorded between models and between brands in relation to cost. Shoe performance was comparable between walking and running trials on a treadmill. No significant difference was observed between shoes and test occasions in terms of comfort. Conclusions: Low- and medium-cost running shoes in each of the three brands tested provided the same (if not better) cushioning of plantar pressure as high-cost running shoes. Cushioning was comparable when walking and running on a treadmill. Comfort is a subjective sensation based on individual preferences and was not related to either the distribution of plantar pressure or cost.

A study of telephone screening and direct observation of surgical wound infections after discharge from hospital

Post-discharge surveillance of surgical site infection is necessary if accurate rates of infection following surgery are to be available. We undertook a prospective study of 376 knee and hip replacements in 366 patients in order to estimate the rate of orthopaedic surgical site infection in the community. The inpatient infection was 3.1% and the post-discharge infection rate was 2.1%. We concluded that the use of telephone interviews of patients to identify the group at highest risk of having a surgical site infection (those who think they have an infection) with rapid follow-up by a professional trained to diagnose infection according to agreed criteria is an effective method of identifying infection after discharge from hospital.

Long-term effect of lithium maintenance therapy on estimated glomerular filtration rate in patients with affective disorders: a population-based cohort study

BACKGROUND For more than 40 years, the long-term effect of lithium maintenance therapy on renal function has been debated. We aimed to assess the effect of lithium maintenance therapy on estimated glomerular filtration rate (eFGR) in patients with affective disorders, and explore predictors for a decrease in eGFR. METHODS This population-based cohort study included adult patients (18-65 years of age at baseline) in Tayside (Scotland, UK) who had recently started on lithium maintenance treatment between Jan 1, 2000, and Dec 31, 2011 (retrospectively assigned to the lithium group) or those with exposure to other first-line drugs used in the treatment of affective disorders (quetiapine, olanzapine, and semisodium valproate) during the same period (retrospectively assigned to the comparator group). Patients had to have at least 6 months of (incidence) exposure to lithium or any of the comparator drugs, at least two eGFR values available in the observation period (one at baseline and at least one after ≥6 months post baseline). We excluded patients with previous exposure to lithium or one of the comparator drugs, those with a previous diagnosis of schizophrenia or other psychotic disorder, those with glomerular disease, tubulo-interstitial disease, or chronic kidney disease stages 4-5 at baseline, and those who had undergone renal transplant before exposure. Maximum follow-up was 12 years. Data were provided by the University of Dundee Health Informatics Centre, who have access to health-related population-based datasets containing data for every patient registered with a regional family doctor. Each patient has a unique ten-digit identifier, the Community Health Index, enabling us to link laboratory tests, dispensed community prescriptions, Scottish Morbidity Records, and mortality records to the patient. All data were anonymised according to Health Informatics Centre standard operating procedures. The primary outcome was the change per year in the eGFR, adjusted for age, sex, and baseline eGFR, and analysed by random coefficient models. FINDINGS 1120 patients (305 exposed to lithium and 815 to comparator drugs) qualified for inclusion, providing 13 963 eGFR values over 12 years. The mean duration of exposure to lithium was 55 months (SD 42; range 6-144). Mean annual decline in eGFR (adjusted for age, sex, and baseline eGFR) was 1·3 mL/min per 1·73 m(2) (SE 0·2) in the lithium group, which did not differ significantly to that in the comparator group (0·9 mL/min/1·73 m(2) [SE 0·15]). After adjustment for additional confounders, the monthly decline in eGFR attributable to lithium exposure amounted to 0·02 mL/min per 1·73 m(2) (SE 0·02, p=0·30). As a post-hoc secondary outcome, we estimated the annual decline in eGFR for the lithium group to be 1·0 mL/min per 1·73 m(2) (SE 0·2), which again did not differ significantly to that in the comparator group (0·4 mL/min/1·73 m(2) [SE 0·2]. Modelling identified significant predictors for eGFR decline as age, baseline eGFR, comorbidities, co-prescriptions of nephrotoxic drugs, and episodes of lithium toxicity; however, duration of exposure to lithium and mean serum lithium level were not significant predictors for eGFR decline. INTERPRETATION Our analysis suggests no effect of stable lithium maintenance therapy (lithium levels in therapeutic range) on the rate of change in eGFR over time. Our results therefore contradict the idea that long-term lithium therapy is associated with nephrotoxicity in the absence of episodes of acute intoxication and that duration of therapy and cumulative dose are the major determinants of toxicity. FUNDING None.

Do patients with diabetes wear shoes of the correct size

Background:  Fifteen per cent of patients with diabetes will develop a foot ulcer at some point in their life. Ill‐fitting footwear frequently contributes to foot ulceration. A good fitting shoe is an essential component in the management of the diabetic foot. The objective of this study was to assess the feet and footwear of patients with diabetes to determine whether they are wearing the correct‐sized shoes.

Shoes influence lower limb muscle activity and may predispose the wearer to lateral ankle ligament injury

Lateral ankle ligaments are injured by hyperinversion of the foot. Foot position is controlled by the lower limb muscles. Awareness of foot position is impaired by wearing shoes. We aimed to determine the influence of wearing shoes upon muscle activity. Sixty‐two healthy subjects underwent the same measurements, barefoot and with standardized shoes in a random order. Electromyography (EMG) was recorded from the peroneus longus muscle in response to sudden and unanticipated inversion of the ipsilateral foot. Following foot inversion, the EMG signal showed an initial peak muscle contraction followed by a sustained smaller contraction. Both changes were significantly greater in shoes compared to the barefoot condition for all tested degrees of inversion. Muscle contraction following sudden inversion of the foot was significantly greater when wearing shoes. This greater muscular contraction may be an intrinsic mechanism to oppose the increased moment created by the inverted foot/shoe condition, and hence, may counter balance the increased tendency to injure the lateral ankle ligaments created by wearing shoes.

Foot pressure in clubfoot—The development of an objective assessment tool

BACKGROUND There are no universal criteria for the assessment of clubfoot. The ideal method should assess functional deformity reliably and objectively. Biomechanical techniques have also been suggested but their role remains undefined. OBJECTIVE This study aimed to assess surgically corrected clubfeet by biomechanical means with the intention to develop certain ratios to aid in objective assessment. METHODS Thirteen children (16 feet) with idiopathic clubfoot, who had previously undergone surgery (lateral-posteromedial release), were reviewed. Various clinical measurements were collected and symptoms assessed using a specially designed questionnaire. Biomechanical (foot pressure) parameters were obtained using two systems: Podotrack and Dynamic Pedobarograph. RESULTS The results showed that foot pressure data were able to demonstrate abnormalities in foot posture and pressure distribution, which could objectively identify clubfoot deformities. In particular, ratios were calculated, which could be used to determine severity and monitor progression. CONCLUSION This study suggests that foot pressure analysis should be routinely used in the assessment of clubfoot. The ratios calculated would be of immense help to the clinicians in monitoring the success of treatment and for early prediction of relapse in patients treated for clubfoot.

The effects of off-the-shelf in-shoe heel inserts on forefoot plantar pressure

Off-the-shelf heel inserts are used widely without adequate scientific information regarding their effects upon the forefoot. The aim of this study was to assess whether the use of in-shoe heel inserts affects the plantar pressure distribution under the forefoot. Thirty-five asymptomatic volunteers consented to participate. Six brands of off-the-shelf heel inserts were tested. Subjects walked along a 10 m walkway with no inserts and then with each pair of inserts, in a randomised order. The Pedar system was used to record in-shoe plantar pressure data. The results confirmed that heel inserts increased pressure under the metatarsal heads and altered the biomechanics of the foot even in asymptomatic subjects. The findings suggested that heel inserts should be used with caution especially in people predisposed to foot problems. The classification of these inserts as an over-the-counter product may need to be reviewed.