Economic analysis and healthcare implications of underdiagnosed idiopathic normal pressure hydrocephalus in Italy's...

Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible neurological condition predominantly affecting individuals over 65 years of age. Despite its treatability through cerebrospinal fluid (CSF) shunting-with clinical improvement in up to 80% of appropriately selected patients-iNPH remains substantially underdiagnosed, with only approximately 13% of affected individuals in Europe receiving appropriate care. This study evaluates the long-term epidemiological and economic burden of iNPH underdiagnosis in Italy over the decade 2024-2033, quantifying potential savings achievable through systematic diagnosis and surgical treatment.

A dual-scenario epidemiological modeling approach was employed using Italian demographic projections from ISTAT for the population aged ≥ 65 years, stratified into two age cohorts (65-79 years and ≥ 80 years). Scenario 1 applied a conservative pooled prevalence of 1.30% derived from an international systematic review; Scenario 2 applied realistic age-stratified rates from a prospective Swedish population-based study (2.1% for ages 65-79; 8.9% for ≥ 80 years). Per-patient annual care costs (€35,866) and surgical intervention costs (€11,803) were modeled with an annual inflation adjustment of 1.78%. The Incremental Cost-Effectiveness Ratio (ICER) was calculated using a reported QALY gain of 1.7 following shunt surgery.

The Italian population aged ≥ 65 years is projected to grow by 16.7% over the study period, reaching 16.77 million by 2033. Estimated iNPH cases range from 186,812 (Scenario 1, conservative) to 611,435 (Scenario 2, realistic) in 2024, increasing to 217,967-707,882 by 2033. Cumulative ten-year costs to the Italian National Health System (INHS) and families without intervention ranged from €145.53 billion (Scenario 1, conservative) to €475.19 billion (Scenario 2, realistic). Systematic shunt surgery could generate cumulative savings ranging from €113.21 billion to €369.74 billion across all four modeled scenarios. The ICER was consistently -€14,166.47/QALY across all scenarios, establishing CSF shunt surgery as an economically dominant intervention.

iNPH underdiagnosis represents a major and escalating economic and clinical challenge for Italy's aging healthcare system. Even under the most conservative scenario, the magnitude of avoidable costs is substantial. The consistently negative ICER confirms that CSF shunt surgery simultaneously reduces healthcare expenditure and improves patient outcomes. Urgent investment in standardized screening programs, enhanced clinical awareness among physicians, and integrated care pathways is required to address this preventable burden.