Cusums to measure chronic daily headache

Area of Science:

• Neurology
• Clinical Trials Methodology
• Statistical Analysis

Background:

• Chronic daily headache (CDH) presents a significant challenge in headache treatment.
• Current clinical trial methodologies for CDH lack standardization, often relying on fixed 28-day observation periods.
• Twenty-eight-day intervals are also common for reviewing stepped-care patient management strategies.

Purpose of the Study:

• To evaluate the utility of cumulated summed differences (cusums) for detecting effective interventions in chronic daily headache (CDH).
• To determine if cusums can identify treatment efficacy earlier than the conventional 28-day observation period.

Main Methods:

• A theoretical patient model with daily headache scores exhibiting maximal variation over 28 days was developed.
• Cumulated summed differences (cusums) were calculated for a control dataset and correlated with time.
• Intervention sensitivity was assessed by observing the departure of post-intervention cusums from the 95% confidence interval of the control data.

Main Results:

• Cusums consistently diverged from the norm when the 28-day model was perturbed with 1 to 17 randomly distributed headache-free days.
• The cusum method detected interventions in less than 28 days when at least 3 headache-free days occurred.
• Reanalysis of a prior magnesium oxide study suggests its negative findings may warrant reconsideration.

Conclusions:

• Cumulated summed differences (cusums) are effective tools for detecting changes in chronic daily headache (CDH).
• Cusums can be applied to enhance both clinical trial designs and stepped-care treatment algorithms for CDH management.