The calculation instrument displayed good discrimination, with a C-index of 0.72, as well as good calibration, investigators say.
Motor dysfunction is more likely to occur in individuals who meet upper limb involvement, combined diseases, and the number of affected centrums greater than 3, according to a nomogram model for motor dysfunction of limb herpes zoster developed by investigators.
In the study, published by the Journal of Pain Research, investigators included 213 individuals with limb herpes zoster in the First Hospital of Jiaxing from January 2015 to June 2020. In total, there were 58 cases in the motor dysfunction group and 155 cases in the nonmotor dysfunction group.
Individuals were included if they had a diagnosis of herpes zoster that was present in extremities, they had complete clinical data, they had moderate to severe pain with numeric rating scale scores of greater than 2, and they were aged 18 to 85 years.
Individuals were excluded if they had central nervous system-related diseases, nerve compression syndromes, skeletal muscle system-related diseases, or refused to provide clinical data.
The muscle strength of the affected limb was evaluated using the Medical Research Council score, where a score less than grade 5 and lower than the contralateral limb was considered motor dysfunction.
Investigators also used multivariate and univariate logistic regression to determine the factors of motor dysfunction in relation to limb herpes zoster. Additionally, they used R software to develop the monogram of the risk of motor dysfunction.
Discrimination and calibration were assessed by using the C-index and calibration plot, while internal validation was assessed by bootstrapping validation.
Investigators found that the univariate analysis showed that the location of involvement, whether diseases were or were not combined, and the number of affected centrums, were associated with the occurrence of motor dysfunction for individuals with limb herpes zoster.
The multivariate logistic regression analysis showed that the upper limb involvement of non-combined diseases and the number of affected centrums less than or equal to 3 were independent influencing factors of the complication.
Additionally, investigators found that the prediction model displayed good discrimination with a C-index of 0.72, as well as good calibration, while a high C-index value of 0.71 could still be reached in the interval validation.
The study’s limitations included lack of external verification, making additional research necessary to replicate and verify the study’s results.
Large-sample, multicenter, prospective clinical studies with more patient data are necessary to allow a comparison of different algorithm models and establish a more accurate prediction model.
Herpes zoster is a skin infection caused by the varicella-zoster virus, which is most common in elderly individuals, according to the study.
It is characterized by erythema and clustered blisters that are often accompanied severe pain.
According to the study, a total of about 20% to 30% of people will suffer from herpes zoster in their life type, but motor dysfunction is a rare neurological complication, accounting for just 0.3% to 5% of cases.
Tang J, Tao J, Luo G, Zhu J, Yao M. Analysis of risk factors and construction of a prediction model of motor dysfunction caused by limb herpes zoster. J Pain Res. 2022;15:367-375 doi:10.2147/JPR.S346564