Clinical bone health among adults with cerebral palsy: moving beyond assessing bone mineral density alone

Prognostic comparison between GMFCS and WCI for 5-year risks of 22 relevant health outcomes for adults with cerebral palsy: Expanding the methodological menu for prognostic model research

BACKGROUND

The gross motor function classification system (GMFCS) is a well-established measurement of function specific to cerebral palsy (CP) and likely offers prognostic ability for disease trajectories. However, other emerging measurements may be more directly aligned with assessing disease risk for adults with CP, such as the Whitney Comorbidity Index (WCI).

OBJECTIVE

To expand the methodological menu for prognostic model research, this study assessed whether GMFCS or WCI served as a better prognostic factor of 5-year risks of mortality and 21 relevant morbidity outcomes among adults with CP.

METHODS

This retrospective cohort study used medical records from 01/01/2012-06/01/2024 from adults ≥18 years old with CP. A 1-year baseline ascertained the WCI score. Logistic regression estimated and compared the c-statistic of each outcome between: (1) base model (age, sex, race, smoking status, insurance, year of start date) + GMFCS and (2) base model + WCI. Multiple imputation was used for missing GMFCS data to address sample selection bias.

RESULTS

In the complete case analysis with no missing GMFCS data (n = 923), 14 of 21 morbidity outcomes were similarly predicted by base + GMFCS and base + WCI models and 7 were predicted better by base + WCI model, while the mortality outcome was predicted better by base + GMFCS. Using the full cohort after multiple imputation (n = 2601), 18 morbidity outcomes were similarly predicted by both models and 3 were predicted better by base + WCI model, while the mortality outcome was predicted better by base + GMFCS.

CONCLUSIONS

This study suggests that while GMFCS was superior for mortality prediction, the WCI had similar-to-superior prediction for most morbidity outcomes.

Hormonal Control of Bone Architecture Throughout the Lifespan: Implications for Fracture Prediction and Prevention

BACKGROUND

Skeletal modeling in childhood and adolescence and continuous remodeling throughout the lifespan are designed to adapt to a changing environment and resist external forces and fractures. The flux of sex steroids in men and women, beginning from fetal development and evolving through infancy, childhood, puberty, young adulthood, peri/menopause transition, and postmenopause, is critical for bone size, peak bone mass, and fracture resistance.

OBJECTIVE

This review will highlight how changes in sex steroids throughout the lifespan affect bone cells and the consequence of these changes on bone architecture and strength.

METHODS

Literature review and discussion.

RESULTS

The contributions of estrogen and testosterone on skeletal development have been difficult to study due to the reciprocal and intertwining contributions of one on the other. Although orchiectomy in men renders circulating testosterone absent, circulating estrogen also declines due to testosterone being the substrate for estradiol. The discovery of men with absent estradiol or resistance to estrogen and the study of mouse models led to the understanding that estrogen has a larger direct role in skeletal development and maintenance in men and women. The mechanistic reason for larger bone size in men is incompletely understood but related to indirect effects of testosterone on the skeleton, such as higher muscle mass leading to larger mechanical loading. Declines in sex steroids during menopause in women and androgen deprivation therapies in men have profound and negative effects on the skeleton. Therapies to prevent such bone loss are available, but how such therapies can be tailored based on bone size and architecture remains an area of investigation.

CONCLUSION

In this review, the elegant interplay and contribution of sex steroids on bone architecture in men and women throughout the lifespan is described.

The age-related association between serum creatinine and cardiorespiratory morbidity and mortality and fractures among adults with cerebral palsy

PURPOSE

Serum creatinine may be an objective biomarker of salient health issues in adults with cerebral palsy (CP). The objective was to assess the age-related association between serum creatinine with 3-year risk of cardiorespiratory morbidity/mortality and fracture among adults with CP.

PATIENTS AND METHODS

This retrospective cohort study used medical records between Jan. 1, 2012 and Oct. 2, 2022 from adults ≥18 years old with CP. The association between baseline serum creatinine with the 3-year risk of all-cause mortality, respiratory/cardiovascular morbidity/mortality, and fracture was assessed by age and sex using logistic regression. The discriminative ability of serum creatinine alone and in conjunction with other variables was assessed.

RESULTS

Over the 3-year follow-up, 8.3% of 1368 adults with CP had all-cause mortality, 25.6% had respiratory morbidity/mortality, 12.4% had cardiovascular morbidity/mortality, and 8.9% sustained a fracture. The association between serum creatinine with outcomes was dependent on age. For younger adults, lower creatinine had a higher odds ratio (OR) for all-cause mortality, respiratory morbidity/mortality, and fracture. For 51-60 year olds, higher creatinine had a higher OR for cardiovascular morbidity/mortality. Serum creatinine alone had modest prediction of outcomes, and generally improved prediction when added to models that included sex and co-occurring intellectual disabilities and epilepsy (c-statistic range, 0.54-0.84).

CONCLUSIONS

Lower serum creatinine may reflect frailty while higher levels may reflect kidney dysfunction, helping to explain the differential associations by age. Serum creatinine may be a useful biomarker as part of risk prediction models for these salient health issues for adults with CP.

Five-year risk of fracture and subsequent fractures among adults with cerebral palsy

Background

Epidemiologic evidence documenting the incidence of fracture and subsequent fractures among adults with cerebral palsy (CP) is lacking, which could inform fracture prevention efforts. The objective was to characterize the 5-year rate of initial and subsequent fragility fractures among adults with CP.

Methods

This retrospective cohort study used Medicare claims from 01/01/2008–12/31/2019 from adults ≥18 years old with CP (n = 44,239) and elderly ≥65 years old without CP (n = 2,176,463) as a comparison. The incidence rate (IR), IR ratio (IRR), and site distribution were estimated for the initial and subsequent fragility fractures over 5-years by sex and age.

Results

The IR of fragility fracture at any site over the 5-year follow-up was similar for 18–30-year-old men with CP (IR = 5.2; 95%CI = 4.4–5.9) and 30–34-year-old women with CP (IR = 6.3; 95%CI = 5.3–7.2) compared to the same sex youngest-old (65–74 years old) without CP (IRR = 1.09 and 0.94, respectively, both P > 0.05), and increased with older age for those with CP. The number of fragility fractures and IR of subsequent fragility fractures was similar for young men and middle-aged women with CP compared to elderly without CP, and increased with older age for those with CP. The proportion of fragility fracture at the tibia/fibula decreased while the vertebral column and multiple simultaneous sites (most involved hip/lower extremities) increased with older age.

Conclusion

Young and middle-aged adults with CP had similar-to-worse initial and subsequent fragility fracture profiles compared to the general elderly population- a well characterized group for bone fragility. Findings emphasize the need for fracture prevention efforts at younger ages for CP, possibly by ~5 decades younger.

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Fracture prevention efforts are focused on the elderly and postmenopausal women.

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Fragility fracture risk is elevated for those with CP across the adult lifespan.

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For men, the risk for 18–29 year olds (CP) was on par with 65–74 year olds (no CP).

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For women, risk for 30–34 year olds (CP) was on par with 65–74 year olds (no CP).

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CP had a higher risk of subsequent fragility fractures that was also premature.

Preventive Care for Adults With Cerebral Palsy and Other Neurodevelopmental Disabilities: Are We Missing the Point?

Preventive care techniques are cornerstones of primary care for people with neurodevelopmental disabilities such as cerebral palsy (CP). However, well-established methods evaluating health constructs may not be applied in the same way for adults with CP, as compared to the general population, due to differences in anatomy/physiology, leading to missed opportunities for interventions, medication modifications, and other primary/secondary prevention goals. One barrier to care prevention comes from misinterpretation of values to capture health constructs, even when measurements are accurate. In this Perspective, we emphasize the need for differential interpretation of values from commonly used clinical measures that assess for well-known medical issues among adults with CP obesity risk, bone health, and kidney health. We provide technical, but simple, evidence to showcase why the underlying assumptions of how some measures relate to the health construct being assessed may not be appropriate for adults with CP, which may apply to other neurodevelopmental conditions across the lifespan.