Clinical risk prediction using language models: benefits and considerations

OBJECTIVE

The use of electronic health records (EHRs) for clinical risk prediction is on the rise. However, in many practical settings, the limited availability of task-specific EHR data can restrict the application of standard machine learning pipelines. In this study, we investigate the potential of leveraging language models (LMs) as a means to incorporate supplementary domain knowledge for improving the performance of various EHR-based risk prediction tasks.

METHODS

We propose two novel LM-based methods, namely "LLaMA2-EHR" and "Sent-e-Med." Our focus is on utilizing the textual descriptions within structured EHRs to make risk predictions about future diagnoses. We conduct a comprehensive comparison with previous approaches across various data types and sizes.

RESULTS

Experiments across 6 different methods and 3 separate risk prediction tasks reveal that employing LMs to represent structured EHRs, such as diagnostic histories, results in significant performance improvements when evaluated using standard metrics such as area under the receiver operating characteristic (ROC) curve and precision-recall (PR) curve. Additionally, they offer benefits such as few-shot learning, the ability to handle previously unseen medical concepts, and adaptability to various medical vocabularies. However, it is noteworthy that outcomes may exhibit sensitivity to a specific prompt.

CONCLUSION

LMs encompass extensive embedded knowledge, making them valuable for the analysis of EHRs in the context of risk prediction. Nevertheless, it is important to exercise caution in their application, as ongoing safety concerns related to LMs persist and require continuous consideration.

Brn3b regulates the formation of fear-related midbrain circuits and defensive responses to visual threat

Defensive responses to visually threatening stimuli represent an essential fear-related survival instinct, widely detected across species. The neural circuitry mediating visually triggered defensive responses has been delineated in the midbrain. However, the molecular mechanisms regulating the development and function of these circuits remain unresolved. Here, we show that midbrain-specific deletion of the transcription factor Brn3b causes a loss of neurons projecting to the lateral posterior nucleus of the thalamus. Brn3b deletion also down-regulates the expression of the neuropeptide tachykinin 2 (Tac2). Furthermore, Brn3b mutant mice display impaired defensive freezing responses to visual threat precipitated by social isolation. This behavioral phenotype could be ameliorated by overexpressing Tac2, suggesting that Tac2 acts downstream of Brn3b in regulating defensive responses to threat. Together, our experiments identify specific genetic components critical for the functional organization of midbrain fear-related visual circuits. Similar mechanisms may contribute to the development and function of additional long-range brain circuits underlying fear-associated behavior.

Current practices and expectations to reduce Electrophysiology catheters environmental impact: a large EHRA/LIRYC European survey

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Boston Scientific

Background

Despite aiming at improving patients’ health, healthcare consumes a large amount of resources and contributes to 4.6% of the global GHG/carbon emissions, 71% of the footprint being due the supply chain. It also produces millions of tons of complex waste per year. Yet, sustainability in EP remains a complex challenge as the performance and safety for patients are critical.

Objective

To set the ground to reduce electrophysiology (EP) catheters’ environmental impact.

Methods

A survey was conducted to poll European EP centers on 24 questions on sustainability practices and expectations.

Results

278, mostly EP doctors (84%, 76% male, 43yo), working in a public environment (89%, >100 procedures/year in 53% and > 500 in 36%) participated. A majority of EP doctors uses 2 to 4 more catheters/sheath per paroxysmal AF ablation procedure. MAPPING/ABLATION catheters are discarded after the procedure (73&78%), with partial re-cycling (electrodes) in 23&26 %. Local/external sterilization is rarely used (12% & 9%).

Catheters’ packaging are discarded in medical or general waste (38 & 31%) while it is recycled in only 19%.

EP Healthcare professionals are highly motivated in being environment friendly in their personal (82%) and in EP practice (62%). They identify a lack of interest from their hospital in 59% (only 16% having an executive in charge). Other barriers are the complexity of sustainability processes (48%), the effort required to change practice (47%), infectious risk (41%), lack of training (37%) and cost (33%). EP Healthcare professionals would favor sustainable mapping /ablation catheters if performances were preserved (60 & 50%). They consider re-use as the most relevant solution (60%) while being currently illegal in some European countries. Packaging should be reduced in size or made reusable. Finally, they consider that regulatory (31%), education (19%) and recommendations by companies (19%) would encourage the field to transition to more environmentally friendly practices. Interestingly, age, gender, type of practice, country or experience did not impact the results.

Conclusion

EP Healthcare professionals demonstrate a willingness to adopt sustainable practices. They consider re-use as the most relevant approach as of today. 60/50 % would favour sustainable mapping/ablation catheters providing preserved performances. Leaping to the next level of sustainability will request development of new sustainable solutions, models and technologies. Reaching this urgent goal will require governments, industry, hospitals and doctors to work closely in a coordinated approach.

A fast-starting mechanical fish that accelerates at 40 m s(-2)

We have built a simple mechanical system to emulate the fast-start performance of fish. The system consists of a thin metal beam covered by a urethane rubber, the fish body and an appropriately shaped tail. The body form of the mechanical fish was modeled after a pike species and selected because it is a widely-studied fast-start specialist. The mechanical fish was held in curvature and hung in water by two restraining lines, which were simultaneously released by a pneumatic cutting mechanism. The potential energy in the beam was transferred into the fluid, thereby accelerating the fish. We measured the resulting acceleration, and calculated the efficiency of propulsion for the mechanical fish model, defined as the ratio of the final kinetic energy of the fish and the initially stored potential energy in the body beam. We also ran a series of flow visualization tests to observe the resulting flow patterns. The maximum start-up acceleration was measured to be around 40 m s(-2), with the maximum final velocity around 1.2 m s(-1). The form of the measured acceleration signal as function of time is quite similar to that of type I fast-start motions studied by Harper and Blake (1991 J. Exp. Biol. 155 175-92). The hydrodynamic efficiency of the fish was found to be around 10%. Flow visualization of the mechanical fast-start wake was also analyzed, showing that the acceleration peaks are associated with the shedding of two vortex rings in near-lateral directions.

[Arterial blood pressure changes, circadian rhythm and arterial elasticity in hemodialysed patients]

An increased blood pressure variability (BVP) and a loss of nocturnal decline in BP could enhance cardiovascular disease. Peripheral resistances and arterial compliance determine systolic BP. BVP could depend on arterial stiffness. We tested this hypothesis in patients with end-stage renal disease (ERSD) who have arterial elasticity impairment. Twenty one ESRD patients (49.9 +/- 16.7 years) 12 mean and 9 women, undergoing maintenance hemodialysis were studied; 19 had treated hypertension. Ambulatory (ABP) monitoring was performed in all patients: BP was measured every 15 minutes in day-time and every 30 minutes at night. Systolic diurnal variation coefficient was calculated as the ratio between standard deviation and the mean of systolic diurnal BP. Nycthemeral BP pattern was evaluated as the ratio between mean diurnal and nocturnal systolic BP (N/D). Pulse wave velocity (PVW), an index of arterial stiffness, was determined between carotid and femoral sites (11.6 +/- 4.22 m/s). These investigations were performed after the midweek dialysis session. We found a positive correlation between PVW and systolic diurnal BPV (stepwise regression F = 12.9, p < 0.01). This correlation was independent of hypertension, antihypertensive treatment, duration of hemodialysis, and erythropoientin. We also found a positive correlation between N/D and PWV (stepwise regression: F = 8.9 p < 0.05). Our study shows that arterial distensibility links BPV and N/D. It is suggested that an arterial distensibility impairment could enhance BPV and modify nycthemeral BP pattern.

Effects of warm ischemia following harvesting of allograft cardiac valves

The clinical use of cryopreserved allograft valves is rapidly increasing. Viability of valve leaflet fibroblasts has been proposed to be critical to durability. Harvesting of allograft valves involves variable warm ischemia times, defined as the time from cessation of donor heart beat to initial cooling for transport. This ischemic period has been implicated as one of the more critical periods of injury to leaflet cell, even though adequate characterization of this potentially injurious phase has never been accomplished. The present study was undertaken to characterize the metabolic response to warm ischemia in a porcine valve leaflet model. Valve handling was similar to clinical valve harvest and transport protocols. Injury was assessed by protein (1H) and phosphorus (31P) magnetic resonance spectroscopy of 224 porcine semilunar valves. Leaflets were analyzed over time for lactate accumulation and ATP degradation. A radiolabelled incubation assay (48 valves) was used to measure proline accumulation by fibroblasts. Electron microscopy was performed on 36 valves with varying warm ischemia times. ATP stores were entirely depleted after 2 h hypoxia (p less than 0.05). However, lactate continued to accumulate over 24 h. Although aerobic metabolism ceased after 2 h warm ischemia, anaerobic metabolism continued for up to 24 h, which may represent an extended window for harvesting fresh tissue for allograft valve implantation.

Degradation of crystallins from a psoriatic patient undergoing PUVA therapy

Comparative physico-chemical and spectroscopic analyses were carried out in human lens proteins obtained from extracts of normal, senile and PUVA cataracts. Mass recovery analysis reveals a large protein concentration loss in the PUVA cataract relative to the normal lens and senile cataract. This protein loss parallels an increase in the degraded polypeptide chains. However, the tryptophan content (2.1 mol/mol of 20 kDa protein subunit) and the apparent fluorescence quantum yield (phi f = 0.056) of the tryptophan residues which are believed to be involved in the development of UV-induced cataracts are unchanged after age-related alterations and/or in vivo photochemistry associated with psoralen (8MOP) photosensitized reactions.

[Leydig cell tumors in adults. Value of ultrasonic diagnosis. Apropos of 7 tumors]

Leydig cell tumors arise from the gonadal stroma and represent two or three per cent of all testicular tumors. They may occur at any age in contrast with germinal tumor. In adults, about 20 per cent occur with endocrine disturbance: gynecomastia or impotence. Ten per cent are malignant and few cases are bilateral. They are small, yellow, brown tumor. Reinke's crystals are observed in 50 per cent and are pathognomonic. They present no necrosis no hemorrhage, no cyst. A benign tumor is difficult to distinguish from a malignant tumor. A vascular and capsular invasion, an infiltrative margin, a bilateral or multiple tumors must evoke a malignant case. Cryptorchidism, even corrected seems to be partly responsible in tumor induction. Ultrasonography can help for a precocious and reliable diagnosis of tumors, specially in case of occult tumors (2 cases). It also helps to survey the controlateral testis (bilateral tumor: 1 case).

Immunoglobulin deposition in localized conjunctival amyloidosis

Immunofluorescent studies were performed on tarsus and tarsal conjunctiva from a 30-year-old woman with blepharoptosis secondary to localized nonfamilial amyloidosis. Both kappa and lambda light chains were identified in abundance in the resected tissue. There was no evidence of any systemic disease or of amyloid deposition elsewhere. Six months after the patient underwent surgery, there was no sign of recurrence. The antigenic determinants of the amyloid suggested that the pathogenesis of localized nonfamilial ocular amyloidosis involves the accumulation of proteins similar to immunoglobulin.

[Retro-peritoneal tumors. Report of 21 cases (author's transl)]

The authors report their experience about 21 cases of retroperitoneal tumors. They emphasise their often late revelation, the frequent malignity and the involvement of the surroundings organs. They insist on the interest of the opacification of urinary tract and angiography and the value of echo-ranging and total body scanner to evaluate the characteristics of these tumors and theirs extensions. Recurrents are frequents and must be operated each time necessary.

Bacillus cereus pneumonia. Survival in a patient with cavitary disease treated with gentamicin

Cavitary pneumonitis due to Bacillus cereus occurred in a patient with acute lymphoblastic leukemia. Pneumonia due to this organism is uncommon and recovery has not been previously reported. The present report is the first description of cavitary pneumonia due to B. cereus with a successful outcome. Recovery was attributed to appropriate antimicrobial therapy and induction of leukemic remission with chemotherapy.

The use of heparin in the treatment of idiopathic rapidly progressive glomerulonephritis

14 cases of idiopathic rapidly progressive glomerulonephritis (I. R. P. G. N.) treated by heparin between 1968 and 1974 were collected by the authors. Extra-capillary crescents (E. C. C.) occurred in 75 to 100% of glomeruli in ten patients and in 50 to 75% in four. Gross proteinuria, hematuria and renal failure were always present. 9 patients were admitted with primary oligo-anuric renal failure. 11 patients were treated by repeated hemodialysis before and during anticoagulant treatment. Heparin was given by intra-venous injection every 3 hours for one to two months with Howell times range from 150 to 200% of control. Heparin was the only treatment in 6 cases, and was given with dipyridamole in 4, with prednisone in 3 and with azathioprine in one case. 5 severe or fatal hemorragic complications were observed. The clinical course was usually unfavorable with 5 early deaths, 3 provisional steady-states with 2 late deaths. Six patients were treated by periodic hemodialysis. Repeat kidney biopsies were obtained in 8 patients. The findings suggest that heparin affects mainly the E. C. C. and fibrinoid deposits but not glomerular sclerosis. The inefficiency of all current treatments of primary oligo-anuric IRPGN is stressed. In patients with better initial renal function choice between anticoagulant and/or immuno-depressive drugs must be scrutinized in individual cases bearing in mind potential iatrogenic complications. In equivocal cases, patients should be referred to the chronic hemodialysis and/or transplantation program.