Insulin Resistance Syndrome and Metabolic Syndrome are essentially the same thing – they’re different names for the same clinical condition. “Insulin Resistance Syndrome” was actually the original term, but “Metabolic Syndrome” has become the more widely used name in clinical practice.
Both terms describe a cluster of metabolic abnormalities that tend to occur together:

• • Abdominal obesity (central adiposity)
  • Elevated blood pressure
  • Elevated fasting glucose or insulin

• resistance
• High triglycerides
• Low HDL cholesterol

The name “Insulin Resistance Syndrome” more explicitly emphasises what you recognise as the root cause – that insulin resistance is the underlying driver of these interconnected problems. “Metabolic Syndrome” is perhaps a bit more descriptive of the broader metabolic dysfunction, but it doesn’t highlight the causal mechanism as clearly.
Some clinicians prefer “Insulin Resistance Syndrome” precisely because it points to the underlying pathophysiology rather than just describing the symptoms. This aligns with your approach of addressing insulin resistance as the root cause rather than treating each component separately.
The terms are used interchangeably in medical literature, though you’ll see “Metabolic Syndrome” more frequently in current diagnostic criteria and clinical guidelines.