Generalized pairwise comparisons of prioritized outcomes are a powerful and patient-centric analysis of multi-domain scores

BACKGROUND

Generalized pairwise comparisons (GPC) can be used to assess the net benefit of new treatments for rare diseases. We show the potential of GPC through simulations based on data from a natural history study in mucopolysaccharidosis type IIIA (MPS IIIA).

METHODS

Using data from a historical series of untreated children with MPS IIIA aged 2 to 9 years at the time of enrolment and followed for 2 years, we performed simulations to assess the operating characteristics of GPC to detect potential (simulated) treatment effects on a multi-domain symptom assessment. Two approaches were used for GPC: one in which the various domains were prioritized, the other with all domains weighted equally. The net benefit was used as a measure of treatment effect. We used increasing thresholds of clinical relevance to reflect the magnitude of the desired treatment effects, relative to the standard deviation of the measurements in each domain.

RESULTS

GPC were shown to have adequate statistical power (80% or more), even with small sample sizes, to detect treatment effects considered to be clinically worthwhile on a symptom assessment covering five domains (expressive language, daily living skills, and gross-motor, sleep and pain). The prioritized approach generally led to higher power as compared with the non-prioritized approach.

CONCLUSIONS

GPC of prioritized outcomes is a statistically powerful as well as a patient-centric approach for the analysis of multi-domain scores in MPS IIIA and could be applied to other heterogeneous rare diseases.

Réactions dans le sulfolane. V. Ions trihalogénures

Equilibria between I2 and I−, Br−, Cl− in sulfolane were studied by potentiometry and spectrophotometry at 30 °C. The stabilities of Br3− and Cl3− were also determined. The stability constants at nil ionic strength were calculated by means of a program: [Formula: see text], 7.23, and 7.23 for Y = I, Br, and Cl; [Formula: see text], 7.33, and 4.11 for X = I, Br, and Cl. The disproportionation equilibria [Formula: see text] were characterized by log Kd = −1.55(Y = Br) and −0.64 (Y = Cl). The stabilities and spectra of the trihalide ions in sulfolane are compared with similar data for other solvents.

Chélates du fer (III) avec des anions dicarboxylates

Complex formation between iron(III) and oxalate, malonate, succinate, glutarate, and acetate ions has been studied by potentiométric and spectrophotométric methods at 25 °C, ionic strength 0.52 ± 0.02, and [Formula: see text] and 0.1 M H+ concentrations. The acidity constants of the dicarboxylic acids and the formation constants of the monochelates of iron(III) have been determined. The stability order is as follows: [Formula: see text].