Summary1. River rehabilitation schemes are now widespread in the UK and elsewhere, but there have been few systematic assessments of their ecological effect, particularly on target organisms such as fish. Fish populations were therefore assessed in 13 lowland rivers using point abundance measures and depletion electrofishing. Each river was sampled in two reaches, respectively containing a small-scale rehabilitation scheme (artificial riffles or flow deflectors) and an unrehabilitated control reach. Detailed geomorphological surveys were undertaken for the two study reaches in each river to assess the physical and hydraulic effect of rehabilitation. 2. There were large qualitative and quantitative differences among rivers and some had relatively impoverished fish faunas. Overall, total fish abundance, species richness, diversity and equitability were not significantly different between rehabilitated and control reaches. This was true for both the sampling methods used. Bullhead Cottus gobio and stone loach Barbatula barbatula tended to be more abundant in rehabilitated reaches, but this was significant only for artificial riffles. There was a significant between-year difference in fish abundance. 3. In general, rehabilitation schemes increased depth and flow heterogeneity, and fish species richness and diversity appeared to respond positively to increased flow velocity in restored reaches. However, there were few significant relationships between the fish fauna and physical variables, indicating that increasing physical (habitat) heterogeneity does not necessarily lead to higher biological diversity. We therefore caution against the use of physical responses to rehabilitation as a surrogate or reliable predictor of ecological response. 4. The weak response of fishes to rehabilitation may have been because the schemes were inappropriate in design and scale for low-gradient rivers. Furthermore, fish assemblages may have lacked the potential for recovery because of poor water quality and /or because the schemes were isolated within longer sections of degraded river. More extensive and directed biological monitoring is essential to improve understanding and enable future improvements in the design of schemes and the selection of sites with greater potential for successful rehabilitation. 5. Synthesis and applications. From this substantial sample of lowland rivers, there is little evidence of any general benefit to fish of small-scale instream structures in river rehabilitation. From present ecological knowledge it may be that resources would be better devoted to promoting the development of lateral and off-channel habitats within the river corridor. Physical restoration will be most effective when used alongside other strategies to augment fish populations such as water quality management.
Background: There is strong biologic plausibility to support change in albuminuria as a surrogate endpoint for progression of chronic kidney disease (CKD), but empirical evidence to supports its validity in epidemiologic studies is lacking. Methods: We analyzed 28 cohorts including 693,816 individuals (80% with diabetes) and 7,461 end-stage kidney disease (ESKD) events, defined as initiation of kidney replacement therapy. Percent change in albuminuria was quantified during a baseline period of 1, 2 and 3 years using linear regression. Associations with subsequent ESKD were quantified using Cox regression in Coresh et al.
Summary1. Many lowland rivers in Western Europe have been substantially modified to aid land drainage and support the intensification of agriculture. Although there have been many attempts at rehabilitation, few have been systematically evaluated on ecological criteria. 2. Macroinvertebrates were assessed in 13 UK lowland rivers containing instream rehabilitation structures, seven with artificial riffles (intended to mimic natural gravel riffles) and six with flow deflectors (intended to increase flow, depth and substrate heterogeneity within the channel). In each river, invertebrates were compared between stretches of river with and without rehabilitation structures. 3. Rehabilitated and reference stretches were subdivided into different benthic and macrophyte habitats. Three macroinvertebrate samples were taken once in July/August 1999 from each habitat across all schemes and rivers. Current velocity, depth and substratum particle size were recorded at the same time from each habitat. 4. Artificial riffle benthos had faster current, a coarser substratum and was shallower than reference benthos. Depth and substratum particle size differed little between flow deflector and reference benthos, although velocity downstream of the deflector tip was greater, and velocity in the lee of the deflector lower, than reference benthos. At a habitat scale, the benthos of artificial riffles, but not flow deflectors, had higher abundance, taxon richness and diversity than reference benthos. The impact of artificial riffles was most marked for benthic rheophilic taxa. 5. In all rivers, macroinvertebrate diversity was highest in marginal macrophytes and abundance highest in instream macrophytes. Although invertebrate communities were distinct between artificial riffle (but not flow deflector) and reference benthos, these differences were negligible in comparison to those between benthic and macrophyte habitats. 6. Neither artificial riffles nor flow deflectors had any significant impact on the taxon richness of the benthos or of the rehabilitated stretch of the river as a whole. Invertebrate diversity of rehabilitated stretches related closely to that of reference stretches, indicating that larger scale factors constrained any impact of rehabilitation. 7. Synthesis and applications . Local rehabilitation structures appeared to have minor biological effects in lowland rivers. We suggest that post-project appraisal should be more rigorously applied to rehabilitation schemes, measuring success against more clearly defined goals. We also advocate a greater emphasis on large-scale riparian, floodplain and catchment rehabilitation, rather than small-scale channel rehabilitation. Such a change in approach needs more effective cooperation and collaboration between all catchment users.
BackgroundThe Kidney Failure Risk Equation (KFRE) uses the 4 variables of age, sex, urine albumin-to-creatinine ratio (ACR), and estimated glomerular filtration rate (eGFR) in individuals with chronic kidney disease (CKD) to predict the risk of end stage renal disease (ESRD), i.e., the need for dialysis or a kidney transplant, within 2 and 5 years. Currently, national guideline writers in the UK and other countries are evaluating the role of the KFRE in renal referrals from primary care to secondary care, but the KFRE has had limited external validation in primary care. The study’s objectives were therefore to externally validate the KFRE’s prediction of ESRD events in primary care, perform model recalibration if necessary, and assess its projected impact on referral rates to secondary care renal services.Methods and findingsIndividuals with 2 or more Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) eGFR values < 60 ml/min/1.73 m2 more than 90 days apart and a urine ACR or protein-to-creatinine ratio measurement between 1 December 2004 and 1 November 2016 were included in the cohort. The cohort included 35,539 (5.6%) individuals (57.5% female, mean age 75.9 years, median CKD-EPI eGFR 51 ml/min/1.73 m2, median ACR 3.2 mg/mmol) from a total adult practice population of 630,504. Overall, 176 (0.50%) and 429 (1.21%) ESRD events occurred within 2 and 5 years, respectively. Median length of follow-up was 4.7 years (IQR 2.8 to 6.6). Model discrimination was excellent for both 2-year (C-statistic 0.932, 95% CI 0.909 to 0.954) and 5-year (C-statistic 0.924, 95% 0.909 to 0.938) ESRD prediction. The KFRE overpredicted risk in lower (<20%) risk groups. Reducing the model’s baseline risk improved calibration for both 2- and 5-year risk for lower risk groups, but led to some underprediction of risk in higher risk groups. Compared to current criteria, using referral criteria based on a KFRE-calculated 5-year ESRD risk of ≥5% and/or an ACR of ≥70 mg/mmol reduced the number of individuals eligible for referral who did not develop ESRD, increased the likelihood of referral eligibility in those who did develop ESRD, and referred the latter at a younger age and with a higher eGFR. The main limitation of the current study is that the cohort is from one region of the UK and therefore may not be representative of primary care CKD care in other countries.ConclusionsIn this cohort, the recalibrated KFRE accurately predicted the risk of ESRD at 2 and 5 years in primary care. Its introduction into primary care for referrals to secondary care renal services may lead to a reduction in unnecessary referrals, and earlier referrals in those who go on to develop ESRD. However, further validation studies in more diverse cohorts of the clinical impact projections and suggested referral criteria are required before the latter can be clinically implemented.
Treatment-resistant depression (TRD) is a major contributor to the disability caused by major depressive disorder (MDD). Primary care electronic health records provide an easily accessible approach to investigate TRD clinical and genetic characteristics. MDD defined from primary care records in UK Biobank (UKB) and EXCEED studies was compared with other measures of depression and tested for association with MDD polygenic risk score (PRS). Using prescribing records, TRD was defined from at least two switches between antidepressant drugs, each prescribed for at least 6 weeks. Clinical-demographic characteristics, SNP-based heritability (h2SNP) and genetic overlap with psychiatric and non-psychiatric traits were compared in TRD and non-TRD MDD cases. In 230,096 and 8926 UKB and EXCEED participants with primary care data, respectively, the prevalence of MDD was 8.7% and 14.2%, of which 13.2% and 13.5% was TRD, respectively. In both cohorts, MDD defined from primary care records was strongly associated with MDD PRS, and in UKB it showed overlap of 71–88% with other MDD definitions. In UKB, TRD vs healthy controls and non-TRD vs healthy controls h2SNP was comparable (0.25 [SE = 0.04] and 0.19 [SE = 0.02], respectively). TRD vs non-TRD was positively associated with the PRS of attention deficit hyperactivity disorder, with lower socio-economic status, obesity, higher neuroticism and other unfavourable clinical characteristics. This study demonstrated that MDD and TRD can be reliably defined using primary care records and provides the first large scale population assessment of the genetic, clinical and demographic characteristics of TRD.
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