Table 2 Main HIAD indicators and their potential impact on population health and health inequalities

Public health insurance

Enrolment

Automatic enrolment in public insurance reduces non-financial barriers to coverage (such as time-consuming, hard to understand paperwork or lack of awareness of eligibility) and increases participation rates

[49, 50]

Renewal

The need for frequent (annually or less), active (i.e. needing action from the insuree) renewal increases the likelihood of losing coverage

[51–54]

Cost-sharing (out-of-pocket expenses)

Greater cost-sharing leads to decreases in service use

[55–58]

Drug use appears particularly sensitive to this, as are economically vulnerable individuals and those with chronic diseases

[59–70].

Private health insurance and private expenditures on health

Legality of private insurance for this service

A measure of the public prohibition of a parallel private (insurance and provision) market (see duplicative insurance below).

[2]

Minimum level of coverage mandated by law

The evidence suggests that a minimum coverage mandate (such as mental health parity) increases equitable access to services

[71]

Source of financing

Greater reliance on (unregulated) individually risk-rated insurance decreases coverage and access, but this may vary by service

[72–74]

Tax funded subsidies

Have a positive effect on coverage, though this may vary by service

[75, 76].

Enrolment

Lack of regulation surrounding enrollment practices poses significant threats to coverage and access to health services

[77, 78]

Renewal

Lifetime coverage ensures the highest levels of coverage. Low levels of public regulation increase the likelihood of lost coverage and limited access

[52, 79, 80]

General mechanisms

Type of coverage

(1) Aside from strictly public coverage, most countries favor a mix of public and private sources for health insurance coverage.

[2]

PHI can be:

(2) A duplicate of public insurance, providing a private alternative for services already covered under the public system.

(3) A complement or top-up for services already covered under the public system, as in France; (4) A supplement to public insurance for services uninsured under the public system, as in Canada;

(5) A substitute to public insurance (e.g. for those with high incomes in Germany who can opt-out);

(6) A primary source of health insurance, as in the U.S.

Our preliminary results have already found evidence of other coverage types in addition to these

Level of compulsion for health insurance

Mandated insurance improves access to services, but may not decrease health inequalities, unless it constitutes a mandate for public health insurance

[81, 82]