{"id":19,"date":"2026-08-23T18:49:48","date_gmt":"2026-08-23T18:49:48","guid":{"rendered":"https:\/\/test.rhino-health.org\/?page_id=19"},"modified":"2026-08-27T13:13:41","modified_gmt":"2026-08-27T13:13:41","slug":"pld-phenotypes","status":"publish","type":"page","link":"https:\/\/rhino-health.org\/?page_id=19","title":{"rendered":"PLD & Phenotypes"},"content":{"rendered":"
\n
\n
\n
\n
PLD & Phenotypes<\/div>\n

Prematurity-associated lung disease is not one uniform condition<\/h1>\n

\n RHiNO research has helped show that respiratory disease after preterm birth is heterogeneous.
\n Rather than relying on symptoms or neonatal labels alone, the PLD framework asks what current
\n physiological pattern an individual has, how it arose, whether it is reversible, and how it
\n may evolve with growth.\n <\/p>\n

\n Our discoveries<\/a>
\n Publications<\/a>\n <\/div>\n<\/p><\/div>\n
\n \"Illustrated\n <\/div>\n<\/p><\/div>\n<\/section>\n
\n
\n
Why PLD?<\/div>\n

Moving beyond bronchopulmonary dysplasia alone<\/h2>\n

\n Bronchopulmonary dysplasia (BPD) remains an important neonatal diagnosis, but it does not fully capture
\n the diversity of later respiratory abnormalities seen in children and adults born preterm. RHiNO work
\n therefore uses the concept of prematurity-associated lung disease (PLD)<\/strong> to describe
\n later respiratory impairment more broadly and more physiologically.\n <\/p>\n

\n Key principle:<\/strong> PLD is defined by present respiratory physiology, not by neonatal history alone.\n <\/div>\n<\/p><\/div>\n<\/section>\n
\n
\n
The spirometric framework<\/div>\n

Four patterns based on FEV\u2081 and FEV\u2081\/FVC<\/h2>\n

\n A practical way to classify later respiratory physiology after preterm birth is to consider whether
\n FEV\u2081 and FEV\u2081\/FVC are above or below the lower limit of normal (LLN). This yields one preterm control
\n pattern and three abnormal phenotypes.\n <\/p>\n

\n
\n
PTc<\/div>\n

Preterm control pattern<\/h3>\n

FEV\u2081 \u2265 LLN<\/strong>
FEV\u2081\/FVC \u2265 LLN<\/strong><\/p>\n

This is the preserved physiological reference pattern among preterm-born participants.<\/p>\n<\/article>\n

\n
POLD<\/div>\n

Prematurity-associated obstructive lung disease<\/h3>\n

FEV\u2081 < LLN<\/strong>
FEV\u2081\/FVC < LLN<\/strong><\/p>\n

An obstructive pattern suggesting airflow limitation, with potential links to later chronic obstructive disease.<\/p>\n<\/article>\n

\n
pPRISm<\/div>\n

Preserved ratio impaired spirometry<\/h3>\n

FEV\u2081 < LLN<\/strong>
FEV\u2081\/FVC \u2265 LLN<\/strong><\/p>\n

Reduced expiratory volume despite a preserved ratio, implying physiology distinct from classical obstruction.<\/p>\n<\/article>\n

\n
pDysanapsis<\/div>\n

Prematurity-associated dysanapsis<\/h3>\n

FEV\u2081 \u2265 LLN<\/strong>
FEV\u2081\/FVC < LLN<\/strong><\/p>\n

A pattern compatible with airway\u2013lung size mismatch, where ratio is reduced despite preserved FEV\u2081.<\/p>\n<\/article><\/div>\n<\/p><\/div>\n<\/section>\n

\n
\n
Why phenotype?<\/div>\n

Phenotypes help connect physiology with mechanism, prognosis and treatment<\/h2>\n
\n
\n

Mechanism<\/h3>\n

Different phenotypes may arise from different developmental abnormalities in airways, alveoli or airway\u2013lung matching.<\/p>\n<\/article>\n

\n

Reversibility<\/h3>\n

Bronchodilator responsiveness is not uniform across PLD phenotypes, so \u201cabnormal lung function\u201d is not a sufficient treatment guide.<\/p>\n<\/article>\n

\n

Trajectory<\/h3>\n

Some physiological patterns may be more stable over time, while others may transition as lungs continue to grow.<\/p>\n<\/article>\n

\n

Management<\/h3>\n

A phenotype-based framework creates a more rational route to treatment, monitoring and future interventional research.<\/p>\n<\/article><\/div>\n<\/p><\/div>\n<\/section>\n

\n
\n
\n
Bronchodilator response<\/div>\n

PLD is not necessarily fixed disease<\/h2>\n

\n Single-dose bronchodilator testing has shown that a substantial proportion of abnormal pre-bronchodilator
\n spirometry moves into the preterm-control range after treatment. Importantly, this reclassification differs
\n across phenotypes, suggesting that the reversibility of PLD is heterogeneous.\n <\/p>\n